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
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.
squash bug infestation can hurt the crop; a large population can kill
it. Here's come recommendations to help reduce the damage from this
- 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.
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
|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.
Source: Kelly Allsup,
University of Illinois Extension horticulture educator
Parasitic Tachinid Fly
direct from the grower
Insect Killing Soap
and Garden Center