Scale Insects – Pest of the Month

 Scale at a glance

Type of Damage	Pierce-sucking
Plant Symptoms	Stunted growth, leaf drop, leaf curl, death
Favourite Plant	Many trees and shrubs, citrus especially
Occurrence	Year-round in areas with mild winters (SA)
Distribution	Worldwide
Control	Moderate: physical control and preventative measures preferable, biological control agents available

Cochineal insects on a cactus branch (sizes not accurate)
IA Appleton's Guide to Mexico
1884
Wikimedia Commons

Quick Intro


Scale insects are found across the world in all gardens, whether they have ornamentals or vegetables. Scales are often overlooked due to their small size but easily reach epidemic proportions that can kill off even the healthiest of plants. The best way to control scale is to prevent them from establishing on plants the first time round and to make sure that you control their ‘ant’ herders as well.

Science Stuff

Scale belonged to the previously obsolete Homoptera order, which were insects that had fully membranous wings. Now they have been allocated to the Hemiptera order, which include insects with half of their wings membranous and the other half covered in a thicker elytra. They are placed under the Sub-order; Strenorrhyncha and Superfamily; Coccoidae.

There are 23 families in total, of which 3 are of main concern to edible gardeners:

Coccidae – Soft scale

Soft Scale
Coccidae

These are very small insects, 1-2 mm contained within a waxy shell. They can be a myriad of colours, but the most common are light tan – black. Adult females lose their legs, becoming sessile and remain feeding on the same place for the duration of their life cycle. Males are short lived, 1-2 days, winged and never feed. Therefore the main damage to the plants is induced by the immatures and females.

Monophlebidae – Cottony cushion scale

Australian Bug, Fluted Scale,
Cottony Cushion Scale
Icerya purchasi

These are larger scale insects; immatures are 1-2 mm, whereas adults can be as large as 1 cm. They have soft (do not have a waxy cuticle), white bodies. These are hermaphrodites, meaning that no true males or females are present. They keep their eggs within their bodies and after hatching; bear live young. Adults retain their legs (unusual for scale insects) and limited mobility. 

Pseudococcidae - Mealybugs

Mealybugs
Pseudococcidae

Again, small about 1-2 mm grey or white bugs. They do not have a hardened waxy shell, but secrete a waxy coating onto their bodies and eggs (hence the name mealybug). They can often be confused with mealy aphids that have similar appearance and feed on the same host plants.


Hosts

Woody trees and shrubs are most often targeted, this means any fruit trees or perennial herb are likely to be attacked. Citrus, and its relatives, such as curry plants are most often infested, especially during the winter months when trees become dormant and more susceptible to attack.

Microscopic Scale on underside of curry tree leaf
Soft Scale, Coccidae

Life Cycle

Immature scale can be transported via the wind to new hosts. Afterwards it seeks out a suitable feeding place, such as safe crevices or joints of branches. It will likely remain in the same place throughout its entire life cycle. Depending on the species, there can be one or two nymphal (instar) stages. Most adult female scale, except for mealybugs and cottony cushion scale lose their legs and become sedentary. Males die soon after fertilising females. Many scale species are parthenogenic, where unfertilised females give rise to ‘clones’ without any genetic contribution from the males. Some scale lay eggs outside their bodies, but most retain the eggs under their shell and once the eggs have hatched the adults ‘bear’ live young. Each generation the immatures, known as crawlers, move away from the adults and settle upon new terrain until the whole plant becomes occupied or the nymphs are swept away by the wind to start a new colony elsewhere.

Scale adults and immatures on stems and inside crevices

Control

Multiple natural control remedies are available for scale, although several applications or rounds of scale removal will be necessary to ensure that the entire colony has been destroyed.

Firstly, physical removal is the most successful, but can be labour intensive. This means arming yourself with a blunt butter knife or twig or whatever tool is handy and scrape them from the plant bark. You do not require an excessive amount of force to remove them and once you have dislodged them they will die. I know of somebody who grabs a bucket of soapy water and a brush, then scrubs down her citrus trees when the winter infestation strikes!

Natural chemical control includes the use of horticultural white oil (see my Pest Control page for the recipe). Another option is to mix 50% v/v isopropyl alcohol with 1% w/v SDS, the alcohol dissolves the waxy cuticle and the SDS attacks the soft body beneath. Now I don’t think that these chemicals are too readily available to the public, so you can substitute it with ethanol and sunlight liquid – The exact quantities would be determined through some trial and error whereas the effect on the plant might be unknown (I would recommend avoiding the leaves of the plant should you wish to go this route).

Another alternative is diatomaceous earth, which contains small sharp particles that cut the bodies and leads to desiccation. This will control both the scale and ant herders, but might be a bit hard to come by or expensive.

Several insects parasitise or predators prey upon scale. Those that make up the front line in biological control are:

Biological Control Agent	Parasite or Predator	Prey species
Parasitic Wasps	Metaphycus helvolus, Encyrtus spp., Encarsia citrinia, Aphytis spp., Coccophagus spp.	Coccus hesperidum, Saitettia coffeae
Parasitic fly	Cryptochaetum iceryae	Icerya purchasi (cottony cusion scale)
Ladybirds, ladybeetles or ladybugs	Chilocorus spp., Hyperospisspp., Rhyzobius spp. Rodolia cordinalis (Vedalia ladybug)	Various species Icerya purchasi (cottony cusion scale)

The tiny parasitic wasps are most effective in greenhouses as they are simply swept away by the wind in outdoor gardens. Ladybeetles are more readily available, but will only arrive and remain in the garden if the scale populations are very high. Ladybeetle larvae feed beneath the scale insects and some of the adults resemble scale insects, such as the Mealy bug destroyer, so be careful not to harm them during your scale control efforts. Please refer to my Ladybird and Wasps Biological Control Posts for more detail information about each insect.

Preventative Tips

The old adage that ‘Prevention in better than Cure’ certainly applies to scale insects. This comes down to two crucial points:

1) Prevent scale attachment
2) Limit ant access

This can be done by applying Petroleum jelly, such as Vaseline, to the base of the tree or shrub BEFORE infestation. Scale insects cannot move past this barrier which effectively keeps them off the plants. BUT, ants – AKA herders – seek the honeydew (sugary secretion) that scale and other pests produce. Ants will actively tend, protect and transport scale to hosts plant to keep them like cattle and harvest the honeydew. This is the biggest problem, because the ants do figure out how to manoeuvre over the Petroleum jelly and bring along their herds.

Scale and Ant Herders

I have found that fresh Vaseline (still sticky) works very well until it becomes clogged with dust or develops a crusted layer. So depending on the season and weather you would need to replace the Vaseline once every few months. Also any support ties between the plant and stakes or other supports (such as ties to a nail in the wall or I tie the trees to some of our burglar bars) also need to be Vaselined or else the ant tightrope walk along the ties to gain access to the host plant once more.

Ant and Scale Vaseline barriers
Cover all bases and access points

The Vaseline should be applied about 20-30 cm from the ground on the stem if possible in order to prevent it from becoming dirt-clogged too quickly due to soil back splash when it rains.

Another option is to get double-sided tape and stick them onto the stems and other access point. I haven’t tried this yet, but I am planning to in the near future. The same applies to the double sided tape – once enough dirt has settled onto it, it becomes useless.

I have Vaselined all my fruit trees and it makes the world of difference to keep the ants and associated pests (aphids and scale) off the plants in the first place. The honeydew is not only attractive for ants to eat, but the affected leaves soon become breeding grounds for black sooty mould that weakens the plants even more.

Something Interesting: Carmine Dye

One would believe that scale insects are merely an agricultural pests and that no good has ever come from them, but surprisingly a certain group of scale insects have been used to make dye since the middle ages. 

Cochineal Dyed Wool
Saintswithin
Wikipedia

Cochineal insects, a type of mealybug, are soft-bodied, oval shaped and use their beak-like mouthparts to feed on members of the Opuntia cacti (this includes the Prickly Pear). As with many other scale, female cochineal insects are wingless, but have limited mobility and form the bulk of the infesting colony.

They originate from Mexico and South America where they have been raised on cacti for the red substance they produce within their bodies. This is carminic acid (19-22% of a mealybug's body), which is a predator deterrent and when mixed with either aluminium or calcium salts it becomes a red carmine dye. This dye is one of the few naturally derived dyes that is a water-soluble colourant yet remains resistant to degradation, light, heat and oxidation. It is more suited to the dyeing of animal derived fabrics and is also used in cosmetics (lipstick, blush) and food colouring (labelled E120), since it is less allergenic and more stable than many synthetic colourants. 

Cochineal insect
Dactylopius coccus
Carminic acid

- Update September 2015 -

Just a quick note on the Vaseline barrier on the tree trunks. Some trees do not seem to appreciate this Vaseline collar (such as the Brush cherry) and don't form any new bark at the collar site (likely too moist). This means you will end up with a restricted trunk at the collar and a weakened trunk. Therefore I suggest checking up on the collars just to make sure. If you notice restrictions occurring remove the Vaseline from the afflicted tree.

Alternatively you can use the white oil or bicarb/sunlight solutions along with a soft bristle brush to scrub off the nasties - no need to take off any bark in the process, only enough to dislodge the scale.

Good luck!

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Please share with fellow gardening enthusiasts via the various sharing buttons at the end of posts/pages! Else you can vote for posts through the Google reactions bar at the end of articles. To stay up to date I have provided several reader and social networking platforms with which to subscribe: Twitter, Pinterest, RSS Feed Reader or Email/Follow directly using the Blog Followers widget on the left hand side toolbar. Thank you for reading and please feel free to ask if questions arise - I appreciate comments and ideas too! 😆

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Monsters, Garions and Onlics

I have been growing onions and garlic in the garden for quite some time. The onions have been very successful, although the larger bulbs do take there sweet time to develop. The garlic grows fine, but for some reason I have strange things happening to the garlic come harvest time.

The first odd occurrence came when we planted about 40 Hadeco garlic bulbs in the beginning of 2013. These were all planted outside near the veld where the Alfalfa patch is situated. Garlic also takes its time to develop, so they only received as much attention as the Alfalfa (but, the onions that grew there where fine!). When harvest time came around, the garlic well... had disappeared!!! I mean 40+ bulbs just vanished! We still haven't figured out who or what the garlic monster was, but I decided to then plant them in the main garden lest the Garlic Monster strike again.

Our recent oddity regarding my garlic growing endeavours was when I purchased a bunch of cloves in a brown paper bag, about 10 or so. (I can't remember the manufacturer, when I see them again I'll post it here). I dedicated a pot for them and they grew very happily for a few months. Harvest time came round again and I was grossly disappointed, many of the bulbs had hardly developed and others seemed more... oniony...

The minute garlic cloves did not have any proper flavour at all and the oniony ones had such a pungent garlic smell that all vampires would have fled from Ruimsig! Thus investigation into the garlic-onions began...

...We suspected that these garlic-onions are likely the result of garlic x onion hybrids. I have never heard of garlic x onion hybrids before (which I refer to as garions and onlics LOL!) but I have found that there have been attempts to create garlic-onion hybrids for future culinary use. Maybe our bulbs where rejects from the breeding programmes or simply accidents from allium farms, which have lead them to be sold to the unsuspecting home gardener?

I have a link to a patent here that describes the process of establishing a garlic x onion or onion x chive hybrid - Patent US5367111. In this patent the onion (Allium cepa) is the ovum donor and garlic (Allium sativum) is the pollen donor, resulting in a near-intermediate garion/onlic plant. Here is a photo of the one of the garions/onlics from my garden:

Garlic x Onion
Hybrid

The leaves represent that of garlic whereas the bulb is fleshy and layered like an onion. I am not sure about the plants developed from the patent, but these garions and onlics from my garden are definitely not a culinary delight! Alas, I will wait patiently until Hadeco brings out their garlic bulbs in Feb/March to plant once more...

There will be garlic! I will not let Garlic Monsters, Garions or Onlics prevent me from savouring homegrown organic garlic!

[Garlic Monster Picture Credits: Monsters; Aleksandr Obuhov. Garlic; Eric Jewell]


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Please share with fellow gardening enthusiasts via the various sharing buttons at the end of posts/pages! Else you can vote for posts through the Google reactions bar at the end of articles. To stay up to date I have provided several reader and social networking platforms with which to subscribe: Twitter, Pinterest, RSS Feed Reader or Email/Follow directly using the Blog Followers or Follow Your Way widget on the left hand side toolbar. Thank you for reading and please feel free to ask if questions arise - I appreciate comments and ideas too! J

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Dangers of Snail Bait - Please don't use Snail Bait

This post isn't related to the threat of snail bait to your garden, but rather you pets. Earlier today we rushed one of our cats, Diesel to the Veterinary emergency room with a suspected poisoning.

I am quickly going to list the warning signs as a reference for anyone searching for the symptoms that might match these:

Initial (early) symptoms (within one hour of snail bait ingestion):

- Restlessness and fidgety
- Easily scared by normal things, such as other cats sneezing or the wind blowing loudly
- Over reactive, for instance when you pet them they are overly appreciative of the attention than normal

Progressive symptoms (about 2-3 hours after ingesting snail bait):

- Exceedingly restless and scared, cannot sit still or calm down
- Doesn't want to be picked up, but still likes petting and attention
- Looking for dark places to hide, such as in a dark room or under furniture
- Diarrhoea
- Body tremors, swaying and excessive salivation (drooling)

[When I noticed the tremors and salivation, we set out to catch Diesel and take him to the Vet, but this was not easy as he thought that we were chasing him and I think that he was having hallucinations by this point.]

While we were trying to catch him we noticed several of the following symptoms:

- Some disorientation; he still managed to run and jump, but you could see that his co-ordination was not normal
- Trying to vomit
- Confusion; he doesn't seem to recognise you or realise that you are trying to help
- Increased heart rate
- Sweating severely; we noticed that he left wet paw prints on the tiles
- Increased hallucinations, with hissing, fighting and fleeing involved [at this stage he scratched and bit everything and everyone as if we were attacking him].

By this time we managed to get him in the cat carrier and on the way to the Vet. He was panting loudly (almost gurgling) and was still fighting and hissing at things inside his box. I put a towel over his box and we spoke to him in soft tones all the way to the Vet which seemed to calm him down, but he was still fighting and hissing at things in his box every so often.

Severe symptoms (about 4-12 hours after ingestion of snail bait):

- Seizures
- Loss of consciousness
- Coma
- Death


As I am typing out the progression of symptoms you would almost say that it is hard to miss, but snail bait poisoning goes from 'strange behaviour' to 'he needs help now!' in 30 min! First we thought that something had frightened him outside and that he was still scared and would calm down once he realised he was safe. He was fine at around 09h00 then went outside, at 09h30 he was back and being a bit fidgety but not anything out of the ordinary as he has such 'busy' moments at times. At around 10h00 he had moved to the kitchen and ate a bit, went to go sit on the chair, but became increasingly restless. [This was due to his stomach cramping and we recall that he licked his stomach]. We checked him for wounds, but found none and his pupils weren't dilated, yet he was a bit over-reactive and freaky still.

I looked up his symptoms on the internet (at about 11h00) and found that fight trauma or a big scare outside are all in line with his symptoms thus far including the diarrhoea and that we should try to calm him down. I got up to go look for him (likely 11h30) and found him in the window sill where he was behaving increasingly strange. Then I noticed that he was swaying, shaking and drooling. We tried to catch him, but he didn't want to be held, he hissed at us and ran away hiding in my room at first where the curtains were closed [They become light sensitive when poisoned]. We tried to catch him several times again, but he scratched and bit so fiercely that he got away several times. [We didn't want him to run so much, because if it were poisoning, which at this stage we were unsure of, running makes the poison metabolise quicker and symptoms progress a lot faster]. At least he stayed in the house or around the house so we eventually managed to get him in the box (at around 12h15). He had a fever, was sweating, panting and had a very high heart rate at this point.

We explain all his symptoms to the vet (the nurse took one look and rushed him to the treatment room), afterwards we told her that we believe he got poisoned about 3 hours ago. She said that he was in a bad way and that his chances are 50/50 and that they will treat the symptoms, but should he make it through the night he will be OK. We phoned the vet when we got home after some more research and told them we suspect snail bait poisoning, which they were already started treating him for. Now we just need to wait to hear about his condition, but I think that he'll pull through as he is still quite young and healthy.


Additional information about Snail bait and its related poisonings:

- Snail bait contains metaldehyde or methiocarb, unfortunately there is no antidote for metaldehyde, but atropine is given to treat methiocarb poisoning.
- The manufacturers of snail bait use bran, molasses, apple flavouring and corn, most of which resemble the taste and ingredients of pet food.
- Most snail bait comes in pellets, which our pets are conditioned to eat. Apparently they do add a bittering agent to the food, but this does not deter all pets.
 - Snail bait poisonings are accidental and most occur during the spring and summer months when the bait is used to protect seedlings in the garden.
- Snail bait is notoriously fast acting (a few hours), whereas rat poison toxicity can take a few days.
- The first 12 hours are crucial during snail bait poisonings and unfortunately pets will eat them again even when they were poisoned the previous time.



I don't use any chemical or synthetic pesticides in my garden and always promote the use of safe/organic alternatives and given what had just happened to Diesel I am even more resolute to keep it that way. We believe that Diesel might have eaten some of the bait whilst in one the neighbours' gardens.


There are several alternatives to snail bait:

- Snails are mostly active during the night. So you can search for them with a torchlight and collected them in a bucket. You can destroy the snails or feed them to the birds.
- You get adhesive copper tape, over which the snails won't go, and can be applied to the stems or bases of plants.
- Salt perimeters are a bit crude and dis-tasteful, but rather this than pet poisoning.
- Crushed up egg shells at the base or plot perimeter will also deter snails from entering.
- Beer traps. Place some beer in a bowl and sink it into the ground so that it is level with the soil. Snails are attracted to this, fall in and drown. Beer traps are not selective and might capture other insects.

We do not have snails in our garden, so I have never tested any of the above-mentioned alternatives (I know that the salt works, as my parent used to use it in our previous house). It is always best to look for non-toxic alternatives to pest control than to run the risk of poisoning your pest (or some one else's) or your family.

I hope that this article will help any other pet owners to more quickly identify the symptoms (as most of the initial stage symptoms are not mentioned) or to prevent future poisonings. Please remember that all pets metabolise toxins differently and that your cats symptoms might not be the exact same progression or order.



- Update 1 October 2014 -

We had a chat with the Vet who treated Diesel and he said that he suspected that he had been poisoned by Two-step (Albicarb, a carbamate pesticide). He said that it was likely intended as a malicious poisoning of the neighbour's dogs and Diesel might have come across a piece of meat laced with the poison.

After some research on the toxin, I found that the symptoms of pesticide poisoning, (such as carbamates and organophosphates) have very similar to snail bait and that their treatments are the same (atropine, which is a counter-acting drug and not really an antidote). I will leave this post as is for snail bait poisonings (or any pesticide for that matter) and have included the Two-step poisoning as well. The big problem is that pesticide poisoning has similar symptoms to many other problems (such as anxiety) and have overlapping symptoms that makes the identification and diagnosis of one particular poison very difficult. Therefore I will again encourage gardeners to seek non-toxic or organic means for pest control and if you do decide to use pesticide, to use them responsibly, read the instructions and make sure you know their toxicity or possible poisoning symptoms.  

For more information on the status of Two-step poisoning in South Africa, the United States and Spain, please see the following article:

Arnot et. al. 2011. Treatment rationale for dogs poisoned by albicarb (carbamate pesticide). Journal of the South African Veterinary Association. 82: (4). 

The article also mentions that Two-step has a bitter additive, but mentions that most animals do not taste bitter and thus it doesn't deter them from eating the stuff (similar to snail bait).

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Please share with fellow gardening enthusiasts via the various sharing buttons at the end of posts/pages! Else you can vote for posts through the Google reactions bar at the end of articles. To stay up to date I have provided several reader and social networking platforms with which to subscribe: Twitter, Pinterest, RSS Feed Reader or Email/Follow directly using the Blog Followers or Follow Your Way widget on the left hand side toolbar. Thank you for reading and please feel free to ask if questions arise - I appreciate comments and ideas too! J

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Radish: How to Grow - Vegetable of the Month

Radishes stats/requirements at a glance

Ease of Raising:	5/5 – Very easy (plant and leave)
Water:	4/5 – Daily (shallow root system)
Sun:	4/5 – Full sun & shade tolerant
Training:	1/5 – None
Fertilise/Feeding:	4/5 – Every two weeks
Time to Harvest:	2/5 – Soon (1-2 months)
Frost Hardiness:	4/4 – Very Hardy (can’t take black frost)
Uses	Culinary
Most Problematic Nemesis:	Aphids, heat
Container Plant:	Most definitely

Radish, Raphanus sativus by Amédée Masclef
Atlas des plantes de France
1891
Dim Grits
Wikimedia commons

Quick Intro

Radishes are commonly used raw in salads, but I am not too fond of their raw peppery nature. To remove their bite, roast or bake them for a sweet, juicy and crisp root vegetable. Due to their blank taste, you can serve them any way you like with various spices or in soups and stews as part of a whole meal. Considering that they are very expensive to buy and nearly fool-proof to grow; one must always have some in the garden. They are small and can be grown as a catch crop or sown in strange awkward places and therefore no additional space is required to grow radishes, simply fill the spaces between existing vegetables.

History

The radish has a somewhat obscure history; its precise origin and wild state are unknown and currently debated. Some records point to the Mediterranean, but with the discovery of wild forms in India, central China and central Asia, it suggests its evolution in southeastern Asia. It has been cultivated by the Egyptians (7000 BC) mostly for its seed oil (48% of the seed). Later it made its way to China (500 BC) and Japan (700 BC) where larger varieties are grown. Radishes are one of the first crops introduced by the Europeans to the Americas.

"First he ate some lettuces
and
some French beans;
and
then he ate some radishes."

The Tale of Peter Rabbit
1902
Beatrix Potter
Wikimedia Commons (User: Siawase)  

Science Stuff

The radish, Raphanus sativus, belongs to the large family of mostly cool-season vegetables, namely the Brassicaceae (Cruciferae).  This includes several cabbage species and root vegetables, such as broccoli, cauliflower, rocket, kale, turnips and kohl-rabi. 

Easter egg mix of globe radishes

Radishes are grown for their swollen tap roots and four main groups are recognized:

Western/small radish	The radish we are all familiar with, small, red and globe shaped.
Oriental radish	A winter grown radish with mild flavor, also known as the Daikon radish. Some can become 50 cm and 20 kg monsters!
Leaf radish	Used as animal fodder.
Rat-tailed radish	Raphanus sativus (caudatus), are grown in Asia for their young pods. Radish seed oil is used as a potential biofuel.

Growing Radishes

Radishes come in many different shapes, sizes and varieties. Most radishes can be grown year round in SA, but there are some exclusive summer and winter varieties as well.

Radishes are easily raised from seed and germinate quickly within 3-4 days as is common with most cabbage crops. Summer varieties (Raphanus sativus, Reticulata group) can be grown in pots or shallow soil as they are small and the roots grow close to the surface. They thrive in hot sunny weather with good watering to keep them cropping. For a constant supply; sow at two-weekly intervals. Radishes are ready for pulling in 3-5 weeks making them the one of the fastest crops in the garden. Make sure not to leave them longer in the ground than what is necessary else they go woody, hollow and lose their flavour. Summer cultivars include the French breakfast, long white icicle, scarlet globe and cherry-belle. All are small globular, red roots, except for the icicle (which has a fierce bite - you have been warned! J ).

Radish,
Raphanus sativus

Winter radishes (Raphanus sativus, Longipinnatus group), such as the Daikon, need deep fertile soil (which was manured for  the previous crop). The root can store well over winter without becoming hollow, but can be planted year round. Due to their size, they will take longer to mature. Winter cultivars include Black Spanish, China rose and Daikon.

Gensuke Daikon Radish
Rapahanus sativus

Other Radish Tips

Some dappled shade can be provided to radishes that wilt in extreme heat. Hill up ground or mulch around the base of the root once it starts protruding out of the ground to prevent the strong sun from wrinkling its shoulders (a similar phenomenon in beets and carrots known as 'green shoulders', thus all root veg require their shoulders to be covered).

Aphids and other small pests may be a problem when the radishes become stressed, but generally they are trouble free and don't spend enough time in the ground for pests to accumulate. Else you can use one of my environmentally friendly pest controls recipes. 


Harvesting & Storing

Radish pull easily from the ground once they are about the size of a golf ball for the small globed varieties. You can store them in a jug of water in the fridge for 2-3 days, but they are best used fresh.


Seed Collection & Storage

Radishes have perfect flowers that are white, pink or purple. They are self-incompatible and require cross-pollination by insects. They are able to cross with other brassica species, except with cabbages and Brassica oleracea (Kohl-rabi) crops. 

Daikon flowers,
Raphanus sativus var. hortensis raphanistroides 

Once the pods are dry you can collect them and rub them to release the seeds. If soil borne disease is a problem you can hold the seeds at 50oC (122oF) for 15 minutes. The seeds are viable for 5 years when stored in a marked glass jar. Radish seeds germinate in a wide range of temperatures, 7-32^oC (45-90oC) and a minimum of 4oC (40oF) and are therefore suitable for winter and summer germination. 

Radish seeds
Raphanus sativus  

My radishes:

Sparkler from Stark Ayres: A small globular red and white radish, which can be grown during the summer or winter. For the seed packet info, see here.

Radish root
Raphanus sativus 

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Please share with fellow gardening enthusiasts via the various sharing buttons at the end of posts/pages! Else you can vote for posts through the Google reactions bar at the end of articles. To stay up to date I have provided several reader and social networking platforms with which to subscribe: Twitter, Pinterest, RSS Feed Reader or Email/Follow directly using the Blog Followers widget on the left hand side toolbar. Thank you for reading and please feel free to ask if questions arise - I appreciate comments and ideas too! 😆

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Sustainable, Productive and Economical Vegetable Gardening (Part 2): Conservation Agriculture

Winter vegetables
at peak production

Sustainable*:

¹ maintained for long periods of time

² use of natural resources without environmental damage

Productive*:

¹ producing crop yield abundantly and efficiently

² being worthy or satisfactory

Economical*:

¹ making the most of resources

² inexpensive

³ avoid unnecessary waste

⁴ efficient use of time and energy

* Definitions according to the English Encarta Dictionary

These three words are central to my veg garden endeavours and I am constantly improving on these in my growing practices. I have been reading (and have several books) about organic vegetable gardening [now again to clarify, *organic* in the sense of ‘derived from living things or sourced naturally’] but I found that the amount of ideas/information to be limited and that the integration of these ideas as a whole is lacking.

Firstly, organic = expensive, especially when it comes to purchasing these things in South Africa. Example: Seaweed based fertilisers, are very organic and very expensive (when compared to synthetic ones)....

Secondly, organic also means hard to come by (again with respect to South Africa), for instance: Neem oil as a natural pesticide is not readily available on the SA market...

Meaning that most of the options available for South African vegetable gardeners to be organic is either expensive or unfeasible. Therefore, on a shoestring student budget I have to come up with many different or creative ideas on how to achieve organic vegetable gardening. These experiments don’t always work out so great (such as my attempt to grow edible mushrooms failed miserably! LOL!)… but once in a while I manage to stumble upon something really cool and useful. 


I have been doing research into some of the sustainable practices in commercial agriculture and came upon a system (not new by the way) called Conservation Agriculture (CA). With a little patience and planning it can actually work very well in small-scale or backyard garden!

Some of the principles behind Conservation Agriculture (CA) was developed by an agronomist, Edward H. Faulkner in 1943, but was only built upon and fully established years later in the 21st century by various specialists. It aims to increase crop productivity through improved soil health and to reduce the environmental impact of agriculture. Well executed research has been done on the benefits of CA as opposed to more conventional methods (see references listed below). 

Conservation Agriculture has three major principles:

1) Reduced or no tillage: 

Traditionally, tillage or digging (by plough or spade) is meant to break up the soil, allow water to infiltrate and to incorporate nutrients into the soil. It also allowed a way for farmers to easily control weeds and soil-borne disease. In an agricultural sense; digging only allows temporary relief from compacted soils and lower soil layers become more compacted by the weight of heavy machinery (or human bodies standing atop). The long term effect of tillage actually destroys soil structure and causes soil erosion when the bare soil is exposed to wind and rain. 

One of the most ancient tools in agriculture
The Yorck Project
 10000 Meisterwerke der Malerei
DVD-ROM, 2002
ISBN 3936122202
Distributed by DIRECTMEDIA
Publishing GmbH Tomb of Sennudjem
Wikimedia Commons

 In CA, the soil is not tilled or tillage is kept to a minimum, some farmers have even returned to animal-drawn systems to decrease the weight on their soil and have set up permanent foot-traffic areas to prevent soil compaction in the fields. No-tillage allows the soil to remain undisturbed and builds up beneficial populations of soil flora (smaller plant based life) and fauna (arthropods, insects, earthworms, fungi, bacteria and other micro-organisms). No-tillage in combination with a ground cover and crop rotation improves overall soil structure and fertility in the long-term, so much so that in some cases it can out-produce conventional farming methods.

2) Semi-permanent or permanent soil cover:

Generally, cultivated soils (this goes for large-scale agriculture and smaller backyard gardens) are left bare. This exposes the soil to wind and water run-off that does away with your precious nutrient-rich topsoil. Heavy downpours compact the soil and reduces the amount of air pockets inside, which results in poorer water infiltration. Bare soil with large amounts of clay (or even clay poor soils) are more prone to compacting after the winter chill, which results in additional tillage come spring.

Living mulch: Lesser or suckling trefoil (a type of clover)
Trifolium dubium 

A semi-permanent or permanent soil cover by either a permanent stand of crops or green manure or mulch (dead or alive) is essential to improve soil structure. Even a protective cover of 30% derived from crop left-overs is better than to leave it bare. A soil cover keeps down weeds, prevents soil erosion and compaction, through both plant and microbe activity, which increases soil health in the long run. Soil cover provides food for beneficial soil organisms (mostly microscopic fungi and bacteria associated with plant roots). These organisms break down, 'biologically till' and incorporate nutrients from the cover crop back into the soil. Effectively building up layers of undisturbed, nutrient-packed topsoil that isn’t blown away, washed away or lost through leaching (nutrients move into deep layers of soil where they become inaccessible to plant roots).

3) Crop rotation:

Conventional agriculture results in mono-cultured crops, this means large stands of one type of plant species. After several years of planting the same crop in the same soil results in an increase of soil-borne diseases specific to that crop and depletes the soil of certain nutrients. Large crop stands are also easier for pest insects to find; resulting in massive crop losses when pests spread like wild-fire through the fields. Sickly mono-cultured crops are also less resistant and become easily over-run by weeds. To improve crop production, synthetic Nitrogen (N element) fertilisers are used in an attempt to replenish the soil, whereas large amounts of pesticides and herbicides are used to combat pests, diseases and weeds.

Now, you have all likely heard the outrage from all sectors about the use of synthetic fertilisers, pesticides and herbicides, but never got told properly why these products are so bad – you are just supposed to believe all the ranting. I don’t use any synthetic herbicides or pesticides in the garden because most are ‘general’ products. This means that they do not distinguish between beneficial plants (like vegetables) or insects (like bees) as opposed to pest species (such as weeds or aphids), they simply kill everything. Those that are specific (say for aphids only) are generally toxic and have withholding periods before the crops treated with these can be used again. Pesticides/herbicides are very ineffective at controlling pests and weeds. Only 50% of pesticides sprayed over crops through air-crafts actually reach the target crop and in general less than 0.1% of pesticides reaches the target pest, meaning that 99.9% of it is lost and contaminates the environment. Considering that herbicides and pesticides are not ideal, gardeners and farmers can still use them with reduced environmental damage by using them in the correct way, see my post on this issue.

The Nitrogen Cycle

I will discuss synthetic N fertilisers as well. The same principle of correct use that applies to perticides/herbicides applies to N fertilisers: the overuse or misuse of synthetic N fertilisers results in serious environmental damage and leads to cultivated soil destruction. When N fertilisers are combined with irrigation, 30-50% of N is lost through leaching! N fertilisers should be added to the soil as they are needed, by chemically testing the soil and applying what is deficient, but this is rarely done in agriculture or in vegetable gardens. The unfortunate result is that an excess of synthetic N disrupts the microbial activity in the soil. These organisms switch to using up all the Carbon (C element) in the soil and then storing large amounts of N in the soil. What this does is deplete nutrients, reduces soil available carbon (organic matter) and builds up nitrogen; leading to acid and salty soils (known as acidification and salinification). Acid soils cause more nutrients to become unavailable to plants and limits the healthy growth of plants. Convention then would lime the soil to correct this, but only results in a downward spiral towards destroying the soil completely until it can no longer be used for crop production. Some of South Africa’s cultivated soils have become so laden with salts (nitrates derived from nitrogen) that only salt-tolerant crops can be grown in them (See my table below for stats)!

South Africa cultivated soils (2009):

Land usage	Percentage (%)
Arable	12.1
Acidified cultivated	4.11
Salinified	2.14

Arable = cultivated = used to produce crops
Thus, already 51.6% of arable soil has been destroyed through conventional practices, if we don't switch to sustainable means how would we feed all our people?

In order to provide an alternative to synthetic N fertilisers and to improve soil fertility, crops are grown in rotation in CA. Here I am referring to crop rotation, multi-cropping, mixed species cropping and inter-cropping at the same time. Basically, crop rotation is the planting of two or more different plant species in the same field, preferably at the same time, in the same year. What farmers do is it to plant two important food staples, such as wheat and potatoes together with a legume crop, such as beans. In a simple system, you have 4 fields and three fields would be planted with one of each crop and the last would remain empty of crops (fallow) but covered with mulch. These are rotated every six months to prevent nutrient depletion and pest build up. Wheat and potatoes use different nutrients, whereas beans replenish soil N through its association with specialised root bacteria (Rhizobia species). The fallow phase (empty) allows other nutrients and carbon to be returned to the soil, as well as improving its structure through microbial activity. REMEMBER, the fallow phase will still have a protective soil cover, just no harvestable crops!

Example:
Simple crop rotation system in agriculture

Conservation Agriculture has been very successful in Brazil and Mexico where some farmers where able to exceed conventional crop production whilst improving their soil health with every rotation. 



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I am very keen on implementing this in my garden, but I would like to recommend a few things and discuss my overall plan:

1) No tillage: This is awesome and works great for me seeing that digging over the garden is a literal back-breaking experience. If your vegetable garden has or you are starting off with poor soil fertility and poor soil structure I would recommend some tillage at least until the soil doesn’t compact on its own after winter. Then you can comfortably switch over to no tillage and let the microbes do the rest! The time needed before no tillage will be greatly minimised by applying your permanent soil cover and crop rotation schemes!
No tillage saves on time and labour (and money for farmers due to less fuel expenses). The planting of seeds is immediate with no ‘working’ of the soil needed beforehand after the fallow phase has expired.

2) Permanent soil cover: I already mulch with dried grass clippings from the lawn, but I find that there isn’t enough grass clippings for the veg garden and for chicken coop litter. Also, nasty critters by the name of Cutworms live in the grass clippings and every time I mulch I am adding these to the garden! The Horror! I am now moving into a green mulch or ground cover, specifically penny royal between my veg plots and clover inside my veg plots. The penny royal has been very successful, see post – I am still working on the clover and will post updates on that later!

Alternatively you can incorporate other green manures and cover crops into your garden. If you have chickens you can choose green manures that dual as chicken feed! See post on Green Manures and Cover Crops. When you want to plant seedlings or sow seeds, simply lift out a piece of your green manure/cover crop and re-plant somewhere else or feed to the chickens.

Alfalfa
 Green manure & cover crop
Medicago sativa

3) Crop rotation: I have been rotating my crops since the start of my vegetable garden, but the recommended crop rotations (i.e. root plot, leafy veg plot, solanum plot and cucurbit plot) doesn’t really work in small veg gardens; it also doesn't work if you have more/less than 4 plots - I have 7 which makes rotating between 4 types confusing at times... So I will now opt for mixed or inter-planting, where I plant a tomato here and there with a few radishes and beets in between and maybe some parsley and onions… I think that this will create a more dynamic planting scheme, both considering the above ground canopy (tomatoes provide some shade and protection to lower growing crops) and underground system where different root structures occupying one plot. This increases diversity in plants, beneficial insects and soil microbes and should either confuse pests or prevent disease. I will do an update on this method later as well.

Mixed or intercropping of fennel, spinach and lettuce

Alternatives to herbicides, pesticides and synthetic fertilisers: I don’t use any herbicides, I either pull them by hand or plant penny royal to out compete them where they grow (clover will have the same effect). I don’t use any pesticides, I either use green recipes (Pest Control Page), biological control or remove them by hand (which is what I do if the beneficials don't get to them). I have been using synthetic fertilisers, but after reading all the research I have decided to start phasing out these as well and replacing them with more natural alternatives, such as Comfrey, Earthworm Tea and Chicken Manure, Alfalfa and Clover. 

You can also check out the Talborne Organics website for their wonderful range of organic fertilisers and pest control products. For vegetables and fruits I would recommend the Vita - Flower & Fruit, which is a slow release 3:1:5 NPK that you can add to your plots, whereas the Biogrow Biotrissol is a liquid fertiliser with similar NPK ratios of 3:2:5 (the liquid one you can add every two weeks at half strenght to all actively growing fruit and veg). Talborne Organics have an extensive list of distributors around South Africa and should be easy to come by.

Hover fly (Diptera) visiting Pak Choy flowers

Last notes:

Clover is also a legume and able to fix nitrogen (it is related to Alfalfa), see Green Manures, and therefore it is a built-in biofertiliser already active in the garden! The nutrient legumes fix are added to the soil through their residues or addition to the compost heap. I will be on the look out for more alternatives in the future and will post what I come across.

I am very interested and excited to see the results of my ‘new’ vegetable garden management routine and will be sure to keep you all updated. I hope this article has inspired you too and please let me know of your results if you also choose to implement a similar system (or have already)!



All my references (freely available), for further reading:
1) From the WWF (SA) – Agriculture: Facts and Trends South Africa.


Some good information on ‘best practice’ agriculture principles and scary stats on the condition of South Africa’s cultivated lands.

2) From the Agricultural Research Council (SA) – Sustainable Land Management Practices in South Africa (2009)
Information on Conservation Agriculture and other sustainable practices as well as results from on-farm implementation.

3) HOBBS, P. R., K. SAYRE and R. GUPTA, 2008 The role of conservation agriculture in sustainable agriculture. Phil Trans R Soc B 363: 543–555.
An excellent scientific article reviewing Conservation Agriculture and has an awesome table with all the benefits of CA as well as case studies in Mexico and Brazil.

4) MULVANEY, R. L., S. A. KHAN and T. R. ELLSWORTH, 2009 Synthetic Nitrogen Fertilizers Deplete Soil Nitrogen: A Global Dilemma for Sustainable Cereal Production. J Environ Qual 38: 2295–2314.
Another scientific article on the effects of overuse and misuse of nitrogen fertilisers

5) STOCKDALE, E. A., and C. A. WATSON, 2012 Managing soil biota to deliver ecosystem services, pp. 163. Natural England Commissioned Report.
A huge book jam-packed with information on how soil micro-organisms influence soil health, crop production and natural ecosystems.


6) PIMENTEL D. and M. BURGESS, 2012. Small amounts of pesticide reaching target insects. Environmental Development and Sustainability 14:1 1-2.
A two page article summarising the total amount of herbicides, fungicides and pesticides used by the US, how much actually reaches target insects and how expensive it is to maintain such practices.

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Previous articles in this series: Sustainable, Productive and Economical Vegetable Gardening 

Part 1: Vegetables worth growing






- Update 14 September 2014 -

Here is an article regarding conservation agriculture in sub Saharan African and its impact on small holder farming communities;

IFAD social reporting blog: Does conservation agriculture work for smallholder farmers in Africa? New report highlights key points for action. Ricci Symons, 29 August 2014.

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