Squash bugs spend the winter to grow to the adult stage and feed on leaves of squash and pumpkin plants. This causes the plant leaves to turn black and dry out. When they feed on fruits this causes scars and sunken areas. Killing the squash bug environmentally is better than using insecticides.
Squash Bugs Can Severely Damage Young Plants
The squash bug which primarily attacks squash, pumpkins and cucumbers is a common garden pest in most areas of the United States. They have sucking mouthparts which they use to suck out the sap from leaves causing them to turn brown. They release a toxin while feeding which can cause the plant to wilt. Younger plants are more prone to squash bugs and can die if they are attacked. Larger plants have more resistance but can still be injured or die if attacked by the bugs in large numbers. Control of squash bugs is very important when plants are young seedlings and are flowering. Adult squash bugs are difficult to kill and it is only early detection of the bugs in the nymph stage that can eradicate the menace. Eggs are laid on the underside of leaves and take 2 weeks to hatch, and the nymphs take an entire season to grow in to adults. Killing the squash bug environmentally is better than using chemicals and pesticides which can also affect the quality of the crop that you grow in your garden.
Image source: Wikimedia: Squash bug : http://commons.wikimedia.org/wiki/File:Coreidae_squash_bug.jpg
It Is Possible To Limit Damage Caused
Damage from squash bugs can be controlled by making very sure that the plants are healthy and fertilized and watered regularly to maintain that condition which can make them more resistant to squash bugs. Planting later in the season can also limit damage.
The physical inspection of the plants and the underside of their leaves will help to spot nymphs, adults and eggs. The insects should be removed and dropped into soapy water. Eggs should be crushed before immersion in the soap water. Squash bugs do tend to congregate under loose boards or newspapers and laying out such items near the plants will find the bugs congregating on them. The board can then be immersed in soap water or the bugs scraped off and given the dunking they deserve. Adult bugs will winter in plant debris and other plant matter. So ensuring a clean garden with no debris or other refuse is one way to keep down the population of squash bugs. The infestation of squash bugs can be avoided by the use of floating row covers on young plants. These sorts of covers do not need any framework for support but would have to be properly anchored to see that they are not blown away. Growing plants on trellis can afford additional protection.
Killing the squash bug environmentally is possible if insecticidal soap is used along with isopropyl alcohol. This should be sprayed on the young plants every two or three days for a fortnight. Neem oil soap is a soap that is effective in killing squash bugs. Suggestions also include sprinkling a combination of wood ashes and hydrated lime in shallow trenches around the plants. The combination should be moistened to keep it from being carried away by the wind. Imitation vanilla around plants also keeps the squash bugs away. Rotenone or dust with sabadilla is a last resort spray to killing the squash bug environmentally. Parasitic flies can be purchased from insect breeders and can help to control squash bugs. You need to attract the parasitic flies by having nectar or pollen producing plants in your garden,. The flies lay their eggs inside the squash bug and thus kill them.
Image source: Wikimedia: Nymphs: http://commons.wikimedia.org/wiki/File:Squash_bug_nymph_1736.JPG