Pest Patrol in the Vegetable Garden

During the mid-summer months it is important to monitor your garden carefully for insect pests. Problems are always easier to manage if caught at an early stage. When you find an insect, try to identify it - there are lots of beneficial insects in the garden that you won't want to disturb. In addition, the best treatment method sometimes depends on the type of insect. If you aren't able to identify the bug, give our master gardener hotline a call for further assistance.

We discovered a number of insects, both friend and foe, on a recent walk through the URI Demonstration Vegetable Garden.

Ladybugs and Other Beneficial Insects

•  We have many ladybugs, dragonflies, tiny parasitic wasps and small bees in the garden this year.
•   These beneficial insects are attracted to the garden by the zinnias, cosmos, alyssum, coreopsis and other flowers and herbs. The flowers provide the insects with nectar and shelter.
•  Learn more about how to attract and keep these good guys happy in the book "Great Garden Companions" by Sally Jean Cunningham. It is an excellent book with good, solid advice on vegetable gardening without chemicals.

Japanese Beetles

• Skeletonized leaves on our butterbean soybeans are characteristic of feeding by Japanese beetle adults.
• We noticed the damaged leaves first and, after close inspection, found several adults. They have greenish-brown bodies, copper-brown wings with white tufts of hair on the edges.
• We controlled the light infestation of Japanese beetles by picking off the beetles the plants by hand.
• For more serious infestations, try an organic insecticide such as BioNeem. It is approved for use in organic gardens.
• For more information, see our factsheet: www.uri.edu/ce/factsheets/sheets/japanesebeetle.html.

Squash Beetles

•  Another insect we've found in the garden is the squash beetle
•  It's related to the ladybug and looks a bit like a ladybug, only larger, more copper-colored and with more spots.
• It is distinctive as a larva (immature) with bright yellow coloring and black bristles.
• Both adults and larvae feed on squash and cucumber plants
• The squash beetle has been able to overcome the chemical defenses of members of the squash family. When a plant in this family is chewed upon, the plant releases a toxic chemical - it's the plants way of defending itself against the insect.
• Before the squash beetle begins feeding, it cuts a crescent in the leaf. This cuts off the supply of the toxin within the leaf so that the beetle can safely feed. Look for crescent shaped lines on the edges of your squash and cucumber plants with chewing damage within the crescent. It is a sure sign of squash beetles.
• The squash beetle damages plant foliage but, although the damage is unsightly, the harvest doesn't appear to be significantly impacted.
• To be on the safe side, we pick off the beetle adults and larvae by hand.
• If the infestation is heavy, try BioNeem.

For more information on insects in your vegetable garden, visit the URI GreenShare factsheet website @ www.uri.edu/ce/factsheets/.