Week 3: June 19, 2018

Good Bug, Bad Bug

This weekend on a farm walk with visitors, we found a real, native lady bug busily foraging on aphids. With today’s technology, it is easier than ever to snap a photo of an insect, upload it to social media and have it identified within a matter of minutes. We also found a similar looking bug called a spotted pink lady beetle that feeds on aphids and the Colorado potato bug larvae. The good bugs reminded us of our first season when we lost several crops to aphids and couldn’t find a lady bug for miles. Since then, it has been a game of good bug versus bad bug.

A conventional farmer might be quick to treat an insect pest with a chemical insecticide. This would work in the short-term, but the pest would eventually return and it would have to be treated again. Overtime, the pest develops immunity to the chemical treatment and the new generations require a new chemical or they flourish because the predator population was never allowed to respond. Much the same as antibiotics in humans and animals.

On the other hand, allowing predators to find the pests will increase the good bug population and over time the two populations achieve a natural balance. Sometimes the predator is another insect. Specific flies and wasps will lay their eggs inside many of our pests. Their young feed on the host and kill it during metamorphosis into an adult. Other times it is a fungus or nematode feeding on the bad bug. Birds hunt in the brassicas for cabbage worms and even tiny shrews scavenge for grubs and maggots under the soil. We still get a few aphids, but we see lady bugs chomping them up almost as quickly as they hatch.

Yes, we do push the natural process at times by increasing the population of “good bugs” to prevent a complete crop loss. But bear in mind that when native species are utilized, they too will run their course and reach equilibrium thus allowing us to farm without synthetic chemicals which are generally detrimental to a wide range of insects including pollinators. Sleep better knowing the food from our farm is not part of an unscripted science experiment on the yet-to-be-determined effects of chemicals on the human body.

Entomologists in training,

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