As spring matures into early summer the green of the new leaves fades just a bit. They are still vibrant but in a stolid kind of a way. The same goes for all the little plants growing in our garden. We have so much hope for them. The little sprouts with such perfect emergent leaves begin to grow and thrive when suddenly they are full of blemishes. In a moment leaves are riddled with holes; crenulated edges appear where there should be none. A gardener’s panic sets in if we don’t instantly recognize the problem.
So, here are five pests that cause gardeners to twitch and moan when they ‘bless’ a vegetable patch with their presence. The organic control strategies here may help you keep those pristine emergent leaves blemish free.
Imported Cabbageworm (Cabbage Butterfly) and Cabbage Looper
The cabbage butterflies and cabbage loopers are moths that love to lay their eggs on our Oh-So- Tasty cruciferous vegetables. Cabbage butterflies are white (see photo) and Cabbage looper adults are brown moths. The eggs are tiny oblong yellowish shapes usually laid on the underside of leaves singly but sometimes in groups. The resultant caterpillars can EAT some LEAF! They are also ridiculously camouflaged. The damage and their dark green droppings give them away.
Prevention of an infestation is the best technique. Using a floating row cover excludes the adults from laying the eggs. Finding and squeezing the little buggers works if you keep up with scouting your plants. If you can’t scout and squish then Bt applications help kill the larval stages of the insect. Garlic sprays can also help in heavy infestations or pyrethrins if you are desperate. The Imported Cabbage Worm adult females can be caught using yellow sticky traps.
These guys leave tiny shotgun shot looking holes in vegetables that belong to the nightshade family as well as other plants. They seem to prefer potato, eggplant, and tomato but will feed on anything really, even our kale this year. They look like little black fleas that will hop away when disturbed.
Exclusion by using a floating row cover can help with these guys, but keep tabs on them by checking the plants regularly. I’ve seen plenty of flea beetles underneath a row cover! These populations peak in spring. Early spring seedlings may succumb to the damage but adult plants rarely do. Once the populations decrease, adult plants can usually withstand the damage remaining insects cause.
Diatomaceous earth can lower populations as well. Some damage is tolerable; if you are concerned about yields, 10-20 % of the leaf area must be removed before yields are affected. A last resort would be to spray neem or pyrethrin. Long term control of the flea beetle population would include use of parasitic nematodes that eat the larval stage that lives in soil.
Check back next week for details on slugs, aphids and mexican bean beetles in Garden Insects, Bugs and Pests! [Part II]