View Full Version : Green Caterpillers - Organic solutions??
15-03-2004, 08:39 PM
This year I have grown a magnificent rockmellon bush. At first I did not realise it was a rockmellon and ate several of the fruit while they were small and green, thinking they wer some sort of warped cucumber (didn't tast too bad) - but that's another story.
Unfortunatelly the caterpillers have gone bullistic on leaves and fruit. It is heart wrenching to see my large fruit being eaten before my eyes while I am waiting ofr it to ripen. As quickly at a kill the catterpillers, more find the fruit.
Any suggestions for good home made organic sprays or other solutions to this problem. I have used pyrethrum a couple of times - but it is pretty ineffective and the amount required to cover the leaves means that this is pretty expensive. Also I don't want to kill the good bugs.
On another topic, has anyone successfuly grown pyrethrum daisies and made their own pyrethrum spray?
18-03-2004, 02:57 PM
hey veggie boy.
i don't think there is any quick fix for grubs of the type you described - go easy on the pyrtherum - it can really set a plant back if used in excess - very toxic.
i'd suggest picking them off by hand and setting up some more long term solutions - a frog pond or something similar.
permaculture is a lot about long term solutions - i know it won't help save many rockmelons in the short term - but in the long term you'll develop a far more balanced system.
18-03-2004, 03:51 PM
For the caterpillars i would try using one part full cream milk to ten parts water and spray all over and under the vines.
You can also use BT (i think off the top of my head it may come under the brand name Bipel). This is non toxic to other critters and allowable under organic certifiers.
PS. my rockmelons are fine as.... guess the chooks are earning their keep :D
21-03-2004, 11:55 PM
I knew an old woman in Queensland who would collect up caterpillars like that and put them into a blender. Give them the 'good news', dilute the liquified caterpillers and spray it back onto the plants being attacked. She did that with a wide variety of insect pests and reckoned that it worked just fine.
(I am not sure if she ever did work out why I would never drink any of the milkshakes she offered me for mowing her yard for her?!)
02-04-2004, 12:13 PM
I just did some reading about green caterpillers today, as we have been getting a little bit hammered by them lately. If I'm right they are the premature form of the white cabbage butterfly. The caterpillers are known here in the US as Cabbage loopers, because of the looping motion the caterpiller uses to move.
The book I consulted, "Organic Plant Protection" recommended using BT, like Chook Nut said, and it explained that this stands for Bacillus Thuringiensis, which is a bacterial pathogen that effects the lepidoptera (moths and butterflies). So what we have here is a form of germ warfare! In my ignorance I had thought that BT was some kind of plant based spray... Seems that with certain crops, like apples, the use of BT can have detrimental effects on benefical predatory insects...
A similar bug spray idea to the one that Jemes recollected is also mentioned in my book, but rather than rely on some homeopathic type reaction from the caterpillers, it suggests hunting for diseased caterpillers, ones infected with NPV Nuclear Polyhedrosis Virus. The symptoms are that they turn chalky white, look half dead and may climb to the top of the plant and lie on the leaves or hang form the underside. Affected worms soon turn black and liquify. Find ten and blend em up with some water, dilute and spray it around. 10 worms will protect up to an acre...
Finally they also recommend the tiny Trichogramma wasp which lays its eggs in the caterpillers. You can get these from commercial biological control insectaries and if you are growing a diverse range of flowers, perenials and other beneficial habitat hopefully they will be able to persist in your permaculture garden...
A thought that has come to my mind is that it would be kind of satisfying to catch the cheeky butterflies in a net on a longish pole... then feed them to the salamander. :;):
02-04-2004, 08:39 PM
Thanks everybody. Some things I can try.
I note that Bacillus Thuringiensis goes by the name Dipel here and is sold by yates. Interestingly they don't mention that it is useful for tomatoes or melons, the two areas that I have been having problems. It is however named in various articles on the web as being useful for these purposes.
Building a frog pond near my veggie patch sounds like a great idea. Anybody got any suggestions for size, design etc...
03-04-2004, 11:48 AM
Another couple of tricks for soft-bodied caterpillars, grubs etc.
Diatomaceous Earth. You can easily buy it in pool shops and the like. It is commonly used inside pool filters and very cheap. It is a sand-like substance made up of the shells of diatoms, a very small marine unicellular algae. The cell walls of this algae are made of silica (basis for glass). A bit like snowflakes, they make a wide variety of amazing shaped cells. Fascinating to look at under a microscope. When you see them, it is hard to believe they are natural constructions. Commonly, the shapes often have very sharp edges and spines.
Scatter a few handfuls around under the bushes affected. Because of their microscopic size, it has the same effect on insects as us crawling over broken glass. Something they find quite unpleasant. If they get into enough bother, it can also kill them. Being silica, the material is quite inert and harmless to anything else.
Another less natural remedy is to use common dishwashing detergent in a weak to medium solution. Put in a normal household spray bottle and spray directly onto the insect. Most insects are small enough that they breathe not by lungs but through osmosis. That is, they absorb oxygen through spicules along their abdomen. (in most cases). Insects are also exoskeleton creatures. That is, they wear their 'skeleton' on the outside. Instead of bone (calcium) it is usually made of a hard waxy material called keretin.
Though I have never seen an 'official' explanation of how detergent works on insects, my best guess is this. The detergent acts to dissolve the waxy exoskeleton just enough to block the breathing spicules on the insect. This effectively smothers the bug as it cannot absorb oxygen.
This works well on flies, cockroaches and the like. Okay, it is still a chemical solution, but a far less harmful one than any kind of insecticide. On larger insects such as cockroaches, it does take a little longer for the effect to take place.
Place the spray on narrow and turn the house into a shooting gallery. Kids love it. And if you use a fairly moderate dilution, it doesn't leave stains behind. Making it a concentrated mix does not seem to noticable improve its efficacy.
Mild detergent in small amounts is usually handled quite easily by gardens. It breaks down in the soil. Sometimes used against aphids etc. More so though as a wetting agent to overcome water-repellant nature of some insects and plants.
There endth today's biology lesson!!
Watch out what kind of diatomaceous earth you use. The stuff from pool shops is a different grade from what can be used for animals and pests. It is larger (even though it still looks extremely tiny) and can cause respiratory problems. I would suggest you sus it out a bit more.
As with any 'safe' pest control, it can still affect other life forms- it will do the same damage to any insect it touches, whether they're friend or foe. It abrades their outer layer, causing them to dry out.
Pool grade has more silica, so it can damage the lungs with its sharp edges. The stuff we want to use has hardly any silica and breaks down more easily, so is less damaging overall.
I've read a bit about d.e. I actually have some of the safe, food grade one, and I'm still sus' on it- mainly as it can get in the air and into your lungs.
A friend gives it to her dogs in their food to kill internal worms. Lots of livestock can eat it, as long as it is the right one.
It can be used in a dustbath to reduce parasites on chooks, too.
But I think utmost care must be taken not to breathe it in at all, wear a mask.
Overall, and to keep it short, Bt is the best thing to use against caterpillers. It will generally only affect caterpillers, and isn't persistent.
23-07-2004, 02:27 AM
I don't know if anyone reads this topic any more, but how about glue spray? Acts as stomach poison to caterpilars & is made of flour & glue. Squashing them against foliage is good to repel & return nutrients if your crop is small enough. I'll give u more later, my best advice always is to read Jackie French, Especially Organic Guide 2 Pests & Diseases.
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