Squash bugs (Anasa tristis) feast on squash, melons, and pumpkins. Adults and the younger nymphs suck the sap from the plants and feed on the fruits, causing moderate to severe plant damage. The feeding damage causes spots, yellowing, and browning of leaves and fruits. The pest can destroy the plant’s runners or side shoots.
Adult squash bugs are similar to stink bugs, but emit an odor only when crushed. Plant debris and leaf litter left in the yard provides shelter for overwintering squash bug adults.
Starting in the spring months, they begin to lay orange-colored eggs on the undersides of squash leaves and stems in a very precise pattern. Nymphs, which resemble spiders, will begin to hatch in 1 to 2 weeks. When first hatched, they stay clumped together.
A squash bug infestation can hurt the crop; a large population can kill it. Here's some recommendations to help reduce the damage from this garden pest:
* Remove areas where adult squash bugs can overwinter by cleaning up garden debris, leaf piles and wooden boards and logs.
* Crop rotation, which means changing the location of the squash and curcubit plants from year to year, can be helpful, as can skipping a growing season.
* Lay down wooden boards to lure adults away from plants.
* Inspect plants for early detection, and pick off eggs, nymphs, and adults.
Parasitic tachinid fly (Trichopoda pennipes)
It is difficult to kill adult squash bugs with pesticides. However, treating plants with horticulture soap, oil, or neem oil will reduce the number of eggs and nymphs without harming beneficial insects and pollinators, such as honey bees. Harsher chemicals are not recommended.
Spraying will be most effective if it reaches all leaf surfaces and stems. Treat at dusk to avoid contact with bees.
An insect called the tachinid fly (Trichopoda pennipes), which lays its pale-colored, oval eggs on the underside or sides of large nymph and adult squash bugs, may also help to keep them under control.