Keeping away garden pests

Do products that claim to keep deer or raccoons out of the garden with a rotten egg smell, the blood or urine of predators, or pepper sprays really work?

Jacqueline Kowalski, OSU Extension Educator for Agriculture and Natural Resources, says, “they have limited effectiveness, but they have to be rotated because the animals get used to that smell or that taste.”

Capsaisin is an active component of chili peppers that is commonly used in synthetic pesticides, often marketed for the policing of deer, groundhogs and other wildlife unwelcome in the home garden. But Kowalski offers two cautions on using pepper sprays to fend off these hungry pests: One, rain will wash them away, and two, they can affect the taste and smell of non-pepper plants.

And what about keeping deer out? “The best [strategy] for deer is at least an eight-foot fence.”

You’ve Got What?!?

Nematodes are tiny worms that live in the soil. With over 20,000 different species, some are parasitic and others are not. Many feast on bacteria or fungi, while some love to devour your tomato, pepper or other plants. Evidence of these little guys is usually malformed flowers, leaves or stems, though some will form “root-knots,” or clumps of ball-like formations on the roots of a plant that block nutrient absorption.

Verticillium wilt is a fungal disease that affects hundreds of types of plants, including some trees and much of what goes into your own home garden. The fungus lives in soil, persisting through winter, and enters plants through tiny feeder roots or damaged roots. It then spreads through the plant and the rest of the garden via spores. Evidence of the disease varies depending on the plant species, but may include a sudden wilting of branches, yellowed foliage, stunted growth, and black streaks on leaves.

Tobacco mosaic virus primarily affects tomato and pepper plants, which are in the same family as tobacco. The virus can lie dormant in the soil for years without a host plant, and will even survive on a gardener’s infected clothing. It is usually spread manually, by humans or animals coming into contact with infected plants then touching healthy plants. For this reason, hand-washing before and after gardening is of utmost importance for avoiding its spread, especially for tobacco users. Though the virus does not generally kill its host plant, it will cause stunted growth, yellowed or curled leaves and flowers that are smaller than normal, and yellow-green spotting on pepper plants.

More on plant pathogens is available at www.missouribotanicalgarden.org.