Offender: Squash Bug. Aka, Anasa tristis.

Squash Bug life cycle

Common Quirks: The adults and nymphs feed in colonies on cucurbits. As they feed they inject a toxic substance into the vine that causes it to wilt and eventually die. They stay mainly on the vines, but later in the season they move to the fruit. Squash Bugs transmit a disease, Cucurbit yellow vine decline, which causes stunting, yellowing, and decline in plant vigor one or two weeks prior to harvest (can you tell I’m quoting something!? 🙂 ). Adults overwinter in under plant debris (which is probably why we’re having such a problem with them now), around buildings, etc. Females lay eggs until midsummer. The nymphs (and adults, if my personal observation was correct) like to congregate at the base of the plant, and will disperse quickly when disturbed. They also stink when disturbed.

Criminal Identification: Squash bug adults are 5/8 in. long and 1/3 as wide. They are usually gray to black with the edges of the abdomen having orange and brown stripes. Nymphs are 3/16 to 1/2 in. in length. Young nymphs have a red head and legs with a green abdomen, however as the nymphs age the red color will turn to black. Later nymphs will be greenish-gray in color with black appendages

What to do: As with all things, early identification of the problem is necessary (we find out now that it’s too late). The adults are very difficult to kill, and it’s probably best to hand pick them off (yeah, it stinks!). There are several natural enemies, but not enough to completely control it. Boards or shingles placed around the base of the plant is one way to easily collect and kill these pests. They will, overnight, congregate under the boards, which will enable you to find them easier in the morning.

Seeing as we’ve got to try something we are going to use a tomato leaf spray. I will try to remember to post about how well that works.