Pesky Pests

The bane of many an organic farmer’s existence is pest problems. Although it is our goal to let wildlife thrive in the garden and withhold the use of dangerous and persistent chemicals, sometimes when I witness an insect population explosion that threatens to knock out a vegetable crop within the matter of a couple days (or even hours!), I admit that a tiny voice in my head screams “Spray baby! Spray!” It can be hard to resist the urge to use pesticides, even when you know better.It is truly amazing how swiftly a new insect will appear in the garden as soon as a crop is planted. Cucumbers sprout one day and the cucumber beetle is there the next! No sooner had the squash seedlings emerged then I began seeing squash bug eggs all over! And the poor potato plants- they seem to attract everything, from potato beetles, to Japanese beetles, to some new invasive we have yet to successfully identify. Just today I saw our fennel being decimated by black swallowtail caterpillars that seem to have appeared overnight.If you want to garden without pesticides, it is essential to pay a lot of attention to your plants every single day. A pest problem can be managed (by squishing bugs) if it is caught in the early stages and if the insect’s eggs can be identified and eradicated. Some bugs, like flea beetles, are too small or active for you to have a hope of catching. For plants that attract flea beetles, like eggplants, radishes and turnips, the best solution is to cover the plants immediately with floating row cover that lets in sunlight but keeps pests out. This is a mistake we learned the hard way and our eggplants really took a hit. We chose to use an organic pesticide called Pyrethrin on our eggplants. As far as pesticides go, Pyrethrin is very safe because it is organic, biodegradable and non-persistent.We’ve also been having a problem with crows pecking at our tomatoes even before they begin to ripen. This is especially hard to watch since tomatoes are such a time intense crop to grow. To rid the garden of crows I put up a “Crow disco”- cd’s strung between our bamboo stakes with twine. The reflection of light off the CDs moving in the breeze will hopefully frighten the crows from coming anywhere near our precious tomatoes.Although nothing but a physical barrier or scare tactics will keep some pests away, like crows, deer, groundhogs, and bunnies, I have been reading a great book by Eliot Coleman called “The New Organic Grower” that presents a fresh take on eliminating insect problems. Coleman explains that there has been a small contingent of researchers and organic growers for over a century that have  found from experience that healthy plants are “inherently insusceptible to pests.” Pest problems are brought about by poor environmental conditions that put stress on plants, leaving them in a weakened, more vulnerable state. From this perspective, it is clear that pests are not the enemy; they are actually a messenger alerting the grower that their plant is not receiving proper care. Rather than the traditional “pest negative” attitude taken by mainstream agriculture, this philosophy is “plant positive.”Here is some of the science behind the “plant positive” mentality:If a plant is stressed, it will stop the synthesis of proteins and simply create new biomass composed of free Nitrogen, which is much easier for insects to digest than complex proteins. It is very hard to find other sources of unattached Nitrogen in nature, so pests will flock to your crop and explode in numbers.A common problem in our industrialized agriculture system is that growers are solely focused on providing the big three macronutrients to plants- Nitrogen, Phosphorous, and Potassium (commonly referred to as NPK); however, a lack of adequate micronutrients in the soil can be a very serious problem for plant immunity to disease and pests. That’s why when I our tomatoes contracted a fungal disease, I opted to use an organic seaweed and fish fertilizer applied to the plant leaves. I’m hoping these added nutrients will give the plants whatever they’re missing to become healthy and immune.If you’re still not convinced by the plant positive mentality, I’ll bet a Thomas Jefferson quote will do the trick, right? In a letter to his daughter, TJ said “I suspect that the insects which have harassed you have been encouraged by the feebleness of your plants and that has been produced by the lean state of the soil.”So it must be true!!That’s all for now folks! I’ll leave you with a photo of the stunning produce our CSA members received last week…Isabel GreenbergMKG Summer Intern