Squash Bug Nymphs

First instar nymphs that had just hatched out of their eggs. They were hairy with light green abdomens, black heads, and black legs. They were about 3 mm long. The eggs were red and elliptical in shape, resembling tiny grape tomatoes. I spotted these nymphs on cucumber plants in an organic garden.

Squash bugs cause severe damage to plants because they secrete highly toxic saliva into the plants. As a result, the foliage wilts, turns black, and dies following feeding. This malady is sometimes referred to as "anasa wilt", which can kill a plant. However, the amount of damage to a plant is directly proportional to the density of the squash bugs feeding on it. Additionally ,squash bugs can vector a bacterium, Serratia marcescens, which causes Cucurbit Yellow Vine Disease. The insects transmit the pathogen and can harbor it within their bodies during the winter. Serratia marcescens is an interesting bacterium because it is opportunistic and different strains can colonize the tissues of both plants and animals. In insects, Serratia is not usually fatal, and squash bugs are not known to suffer any ill effects from infection. However, I once had an entire colony of mosquitoes succumb to a particularly acute infection of Serratia marcescens. The mosquitoes actually turned blood red from the ferocity of the infection.