I'm figuring out what it is so I can post more... I link some photos...
This garden is new and starting with not so great soil... New house.. in Japan... I've started composting and mulching stuff.. but this year and next... soil probably needs a lot of help... So how can I control these things in the short term? Obviously I'm on this list cuz I like to do it naturally... but turning them all into compost is fine with me.
I've lost almost everything.. but we're pretty far south so The sun is still strong even if it cools at night.. so even if I don't get a lot of food from this crop, if I can learn to control them, then I can either greenhouse or do better in the spring.
Whatever they are they don't touch dandelions or basil or other herbs... they like the sweet juicy broad leaves mostly.. though something messed up my carrots as well.
What you got there are cabbage moths. You may have seen a small white moth fluttering around. They lay small black eggs on brassicas and then those green caterpillars will chomp the leaves until they take off and become the moths. Every morning i walk past my tree collards i rub the youngest leaves and pinch any tiny caterpillars i find. If you stay on top of it, it is pretty much a garantee they will be on the inner side of the youngest leaves. Once they start getting to be bigger you will notice bigger holes in every leaf. If you look closely you will see the black eggs and you can remove them with a jet of water or by blowing air. I have not tried any method of control other than manual removal. It is vital to do this daily so on a large plot of brassicas you might have to find another method besides manually removing.
I have a few strategies for dealing with cabbage moths.
They prefer eating some species or varieties more than others, so I plant varieties that are not as susceptible. For example, I almost never see them eating turnips or mustards. Plants with waxy leaves seem less susceptible. Plants with hairy leaves seem less susceptible.
I grow smooth-leaved plants instead winkle-leaved plants. That leaves fewer places for bugs to hide from predators: For example collards rather than cabbage.
In my climate they don't survive the winter, so they blow in on summer winds from warmer climates. I can often harvest spring crops before they arrive. So I don't grow fall brassicas to avoid the moths. I plant early maturing cabbages instead of late maturing.
I cultivate parasitic wasps by providing them with food (small flowers) and nesting sites, and by not poisoning my garden.
I'm seeing mortality of eggs at around temp 8 Cent... is this right? hmm.. so manual control.. anything on companion planting? here we can expect winter temps to dip below 0 which should start the timer over... If I build a small screen house or hoop... control them first by temp/manual... then by leaf type... will check on wasps... anything on natural pesticide or deterrent? Thanks
Location: Cache Valley, zone 4b, Irrigated, 9" rain in badlands.
As far as companion planting, my current tree collard is flanked with squash, lavender, goji, strawberry, lemon balm, spirimint, and a few others, but it has not deturred the moths from laying eggs. In my old forest garden i had good luck with using broccoli as a trap crop for the moths while i grew brussel sprouts, kale, and collards in another part of the garden, i dont know if companion planting aided that or of they just highly prefer broc. The moths seem to flutter pretty much all over, i have not observed them avoiding any particular plants.
I have not thought to try it but maybe DE on the leaf surface would kill The young caterpillars?
I have had success in planting my brassicas in amongst a large variety of other species, both flowers and vegetables--and weeds--at varying heights, and all planted pretty closely (no rows).
This year was a killer year for caterpillars here, and I didn't really follow my own advice, so I had heavy losses, especially my kale. However, some of them have begun to recover, especially the spring cabbage.
Here's a picture of my polyculture garden in June 2013. Can you spot the brassicas? Neither could the cabbage moths! I actually watched them fluttering around, knowing there was something there, but not being able to find anything and eventually flying off.
yep they suck. no matter where i have gardened these guys are around.
one way that i deal with them that seems somewhat effective , and at the very least is totally easy, is to put the hose sprayer on really high and focussed and spray them off. its a bit tedious, because i go over every leaf, use my other hand to hold them against the heavy spray. but it does seems to work ok, not completely get rid of them, but knock them back so far that its not as bad.
another thing i have done is a soapy water spray. sometimes i make a strong tea of pungent herbs - thyme, sage, oregano, garlic, etc...and then use that as the water part for making a simple soapy water spray . i am not sure if this is a huge improvement on just water or what, i dont do it very often though in the past its what i did more frequently.
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