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Success-Oriented Vegetable Gardener, Part 8—More Insects?!
Welcome through Fred's Garden Gate! We've just about reached the end of our veggie-gardening basics discussion. Only a few of the more troublesome insects must be mentioned, before getting on to tying and staking, pinching and pruning and, eventually harvesting. Remember as we wrap up "bugs," our goal is natural control rather than chemical extermination (and contamination).
Stripped Cucumber Beetle
This one-quarter-inch-long, pale yellow insect ranges across the entire eastern seaboard. It is distinguished by three distinct lengthwise black stripes on its wing cases. Most people consider only the adult beetle's damage - they chew on leaves and flowers leaving behind a lacy appearance. But much of the real damage occurs underground by their larvae small grub-like critters which feed on concealed stems and roots.
The key to managing this pest are its worst enemies: various soldier beetles. Golden or dull orange with black markings and a black head, these highly beneficial half-inch-long bugs make quick work of cucumber beetles.
Rotenone dust does a fair job of controlling them but a mixture of lime (1 cupful) and wood ash (1 cupful) in about three gallons of water, sprayed on upper and lower leaf surfaces will do the job even better.
Spotted Cucumber Beetle
Very much like the stripped type, this one is just a little smaller and has 11 or 12 black spots on wing cases. Damage is similar, as is their control. A small, predatory fly takes care of many of these bugs but if things get out of control, rotenone or pyrethrum (a natural substance derived from colorful daisies) will do the trick. Covering plants with cheesecloth or REEMAY floating row cover will prevent their access to young plants.
Adults of both types of cucumber beetles over-winter in plant debris left lying about the garden so it's important to do a bang-up job of post-harvest cleanup. Both also transmit a number of viral wilts and diseases - all the more reason to keep them under tight reins.
Colorado Potato Beetle
This one's the bane of virtually every gardener who grows spuds! About one-third-inch-long, yellow with black stripes and dark spots on its "collar," and with voracious appetites, they infest and consume vast quantities of solanins (eggplants, peppers, tomatoes and, of course, potatoes). They lay bright orange eggs on the undersides of leaves, which hatch into plump, soft-bodied, reddish-orange bugs with a double row of spots running the length of each side. And they multiply fast!
Since adults over-winter in the soil very near where potatoes were planted, one of the best preventatives is crop rotation. Move the solanins around every year...never try to grow in the same spot twice. Post-harvest cleanup, thorough tilling and a dense cover crop will help, too. Hand-picking adults and larvae, and carefully destroying any eggs is about the best most small gardeners can come up with, short of some pretty awful sprays. Rotenone dust sometimes helps but the coverage must be thorough and frequent.
...are always a problem! Adults have wings and they're probably already flying around everywhere. Once again, rotenone dust and pyrethrum will offer some control. Most long-time vegetable gardeners will tell you to plant succulent, flowering annuals like marigolds or nasturtiums around the gardens perimeter. Actually, not a bad idea. They act like aphid-magnets, attracting the little critters away from other, more valuable plants. It's a lot easier to keep an eye on them if they're concentrated on a border of flowers rather than spread throughout the garden.
Encourage predatory insects like lacewings and ladybugs, and spray aphid-infested foliage with soapy water, followed by a rinse of clear water. Safer's Insecticidal Soaps work well, but a squirt of dishwashing liquid in a quart of water is less expensive. Don't forget to rinse.
Dangerous-looking with a pair of sharp pinchers stuck to their rears, earwigs are harmless to humans. But they can do serious damage to flowers and vegetables. They forage at night and hide during the day - a bit of knowledge that'll assist in their control. If you have some bamboo, a length of it—or a short piece of old garden hose—left lying in the garden will make a convenient hiding place for them. Next morning you carefully pick it up and dump its contents into a pail of soapy or oily water. Plop-ploppity-plop...gurgle-gurgle...dead!
Of course, there are many more insects which plague veggie gardeners but if we covered them all we'd be here until the dreaded Y2K brew-ha-ha! Recall that a healthy plant is a more resistant plant...and health is achieved by improved soil condition and nutrition, becoming a "clean" gardener (never leave plant waste lying about, especially over winter), and careful scouting for signs of early insect problems or damage. It's the gardener who stays ahead of serious infestations who wins!
Lastly, remember you're surrounded by experts: Master Gardeners, the Cooperative Extension Service and, best of all, experienced and successful gardeners. Life's greatest bargain is experience gained second-hand!
For the low-down on slugs and snails, their control and - more importantly, prevention, click here.
For more about dealing with weeds, click here
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