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Monday, July 5, 2010

Pest...You Darn Rascals! You will get yours!

I have never been a bug fan. In 7th grade we had to collect bugs as an assignment. Icky, I hated it. Now I find I'm not bug fan in many ways. The pest are killing some of our crops and I need to educate myself on this. Todd has so much more knowledge then I do, but he has been very busy with the new Communication Center that he hasn't been able to work in our garden as he normally does, well that and the weather. Every day off he has it rains, so I am going to attempt to help as much as my knee will allow.

I have been reading up on Squash Vine Boar bugs and Squash Beetle. They have taken a good portion of our squash this year. Here is what I learned about these pest and ways to help prevent.

Squash bug adults are approximately 5/8-inch long, dark brown or mottled, and hard-shelled. They have a long, shield-like shape and membranous-looking wing tips. They give off an odor in large numbers or when crushed.( I haven't noticed this, so maybe we are safe as in not having them in large numbers.) Nymphs are delicate, with bright orangish-red heads, legs, and antennae; the abdomen is green. As the nymphs age, they become grayish-white with dark legs. They range in size from 1/10 to 2/5 of an inch. Squash bug eggs are easy to identify. The orange-yellow eggs are each about 1/16-inch in length. Eggs appear in neatly ordered rows on the underside of host-plant leaves. They gradually change to a bronze color as hatch nears. (I think we are in trouble here. I found several eggs on one of our leaves that are bronze in color. )

Squash vine borers overwinter as larvae or pupae in the soil. Adult moths emerge in the spring and deposit eggs on the plants. Disk-shaped, dark-reddish-brown eggs are laid singly on the plant near the base. After hatching, the larvae penetrate the plant stem and burrow toward the base. An individual adult can lay from 150 to 250 eggs. (That is a lot of bugs.) Occasionally, small borers may also enter leaf stems. The burrowing larvae destroy the whole plant or the invaded runner to wilt and die. Feeding may continue for four to six weeks. A sticky gob of excrement (which resembles wet sawdust) typically marks the entrance site. If a vine dies before the borer has completed its larval cycle, the larva can migrate to a neighboring plant and resume feeding there. The squash vine borer larvae are whitish, wrinkled, brown-headed worms that can grow to about 1 inch in length. The adult moth, a member of the clear-winged moth family, has clear wings with metallic green-black and orange colors on the body and wing fringes. The moth is a day flier, and looks like a wasp. Generally, only one generation per year is produced in northern state.

Iowa State University Organics Research Program conducted trials of various control methods for squash bug and squash vine borer. Researchers found that mulching with newspaper and hay, combined with tightly secured row covers on the plots, provided very effective control of both weeds and squash bugs. Todd did the mulching with newspaper and hay last year in the main garden. This year I think we should do the same to our squash beds.

Other options to help prevent diseases are:
  • Row Covers~physically exclude pests and prevent them from reaching the plants in large numbers. Uncover about the time the female blooms are about to bloom.
  • Plant later in the year, about now. The bugs are less active in July to mid July.
  • An experimental technique for squash bug control is companion planting with repellent plants such as catnip, tansy, radishes, nasturtiums, or marigolds. I have a huge box of marigolds. I recall many gardens with marigolds in it. I guess this flower assists in many ways.
Striped cucumber beetles larval stage only feed on roots of cucurbit plants. Overwintering adults feed on the pollen, petals and leaves of early blooming plants, especially flowering plants in the rose family, in spring before migrating to cucurbit fields. Adults also feed on the leaves and
flowers of corn, beans and peas during the growing season and on goldenrods, sunflowers
and asters later in the season. However, both species of striped cucumber beetles are known as specialist feeders because the beetles highly prefer cucurbit plants and fruits. The beetles produce one or two generations per growing season in northern regions.
Cucumber beetles injure cucurbit crops by:
  • Direct feeding by larvae can injure crop roots and disrupt plant growth. Direct feeding by adults can stunt seedlings and damage maturing fruits.
  • Cucumber beetles transmit bacterial wilt, which causes plants to quickly wilt and die. Bacterial wilt is a major problem for many vegetable growers.
Plants that the Cucumber Beetle prefers: (listed as greatest to least)
  1. cucumber
  2. cantaloupe
  3. honeydew
  4. casaba melon
  5. winter squash
  6. pumpkins
  7. summer squash
  8. watermelon
Row covers can make a difference between harvestable crop and crop failure. However, row covers will need weed control because this will create a favorable environment for weeds. The first 30-40 days the cover can be on or until blooms begin. However it is during this time that it is critical to have no weeds. During this time a weed-suppressive mulch would be great such as plastic mulch, straw, hay, and paper. This is great for cucumbers even if the row covers are not on the seedlings, however this creates a perfect environment for the squash bugs

Most importantly for all pest is to cultivate and residue removal this can help reduce over-winterizing populations

Predators...bats, hunting spiders, web weaving spiders, and especially tachinid flies and wasp.

Information for us to think on and possibly act upon for next year's garden.

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