Skinny green caterpillars on my cabbage

[Troppofoodgardener]

Any advice on the best way to organically reduce these buggers to waste would be MUCH appreciated!! I live in the tropics where the temp is regularly around 89 - 91 degs, so white oil won't work...

[url=https://img209.imageshack.us/I/catpill.jpg/][img]https://img209.imageshack.us/img209/8122/catpill.jpg[/img][/url]

[url=https://img96.imageshack.us/I/catpil.jpg/][img]https://img96.imageshack.us/img96/1301/catpil.jpg[/img][/url]

[Kisal]

That's the second instar of the cabbage looper (Trichoplusia ni).

Have you considered using some other type of oil, such as neem or horticultural oil? They're lighter in weight than white oil, and can be used at higher temperatures.

BT (Bacillus thuringiensis) is effective, but may take about a week to completely clear the infestation. Hand-picking, while time consuming, is also very effective.

In the future, you could use row covers during periods when the cabbage moths are active.

[Troppofoodgardener]

Thanks again Kisal for the answers

Looked up some products here with BT in them.. they seem to be safe, so I will give them a go. So far I've grown everything as organically as I can.. so I wonder if using BT counts as organic?

Guess I've been lucky with the cabbages so far, this is my first infestation of cabbage moth. I have been hand-removing the caterpillars, and it is very time-consuming.

I wish there was some sort of magical zapper that kills all caterpillars and mealybugs in my garden, while leaving everything else alone!!

[Kisal]

For insect larvae, BT might well turn out to be your best weapon, then. It doesn't affect anything except insects.

Here are a few articles about BT and how it works:

https://www.bt.ucsd.edu/how_bt_work.html

https://filebox.vt.edu/cals/cses/chagedor/btprimer.html

https://cecalaveras.ucdavis.edu/bt.htm

[rainbowgardener]

There are genetically modified plants which have been given genes to produce the BT toxins, but home gardeners usually just spray it on. Here in the States it is sold in most garden stores under names like Thuricide. It is a biological, not chemical way of dealing with the problem, so still counts as organic gardening.

However, there is some evidence that BT as present in the GMOs may be harmful to honeybees and perhaps implicated in the colony collapse disorder that is devastating honeybee populations:

https://www.naturalnews.com/025287_bees_honey_crops.html

https://www.gmwatch.org/component/content/article/11621-gm-crops-and-honey-bee-research

This is controversial and not all studies have found the same effects and it is only studied with GMO's not the externally applied BT sprays. Nonetheless, I think the bottom line is that we always need to use the most minimal interventions we can. Any intervention likely has unintended consequences somewhere in the remarkably complex set of interactions we call Nature.

[applestar]

Magical zappers for caterpillars is wasps -- both the tiny beneficial wasps that lay eggs on them and the larger ones that snatch them and feed them to their young.

In my garden, paper wasps and yellow jackets can bee seen crawling all over the cabbage leaves, deep into the areas I couldn't see or reach.

Unfortunately, they're not 100% effective. Red cabbages seem to be less appetizing to cabbage moth and white cabbage butterfly. In my garden last year, row tunnel with insect barrier netting was the best defense, and even then, one butterfly got in.

Interestingly, a single green cabbage that had not been protected with a physical barrier, but was located under a massive 4ft canopy of 2nd year flowering parsley -- lots and lots of beneficial insects not just wasps -- and 2 steps away from a clump of lavender -- huge gathering of wasps of every kind -- was almost completely undamaged except for a few slug holes. There was a paper wasps nest in the fence about 6 ft away as well.

For this reason, I would recommend Bt specific to caterpillars, which affects ONLY moth and butterfly caterpillars over neem. But be very careful of overspray so as not to affect desirable butterfly (or moth) larvae. ( For instance, I would not have sprayed it near the parsley because even though they eat parsley, I like Black Swallowtails and plant extra parsley for them TO eat.)

Surround --superfine kaolin clay-- barrier is supposed to confuse them. I didn't try that this year but may next year.