Pest and Disease Control
Analyze and treat pest problems as they arise. For difficult-to-diagnose problems, take a sample to a local nursery or extension office for help.
The best cure for pest problems is prevention. Healthy plants resist disease and pest problems. Purchase plants and seeds that are disease and pest resistant – check the packaging labels for specific resistances. Disease and pest resistant varieties are marked in most catalogs and nurseries. Nurseries can usually provide additional information.
Maximum plant growth can be achieved by providing plants an optimum growing environment. Make sure vegetable plants receive the right amount of sunlight. Most require full sun for at least 6 hours or longer each day. Prepare soil properly, allow proper drainage, and irrigate only as needed.
Before treating pests with chemical controls, try mechanical controls first. A sharp hoe is still the best weapon against weeds. Hand picking and disposal of insects is often sufficient for control. If chemical controls are needed, diagnose the problem carefully before applying anything. Many pests in gardens are innocuous, causing neither damage nor benefit. Others, such as honey bees are beneficial and should be protected. Some insect pests will be controlled over time by predatory insects such as ladybug beetles and preying mantises.
When chemicals are required, use them according to the directions on the label to avoid harming pets or people.
Monitor plants for signs of pests or disease. If more than half of the plants of a certain variety appear sick, strong measures may be needed. Check the tops and bottoms of the leaves, the stems, the flowers, and the base of the plant.
Look for the following:
- ** Bugs on the leaves, stems, and branches of sick plants
- ** Droppings on the plant or on the ground around the plant
- ** Loose soil mounds around the base of the stem
- ** Leaves which are wilted, yellowed, spotted or curled
- ** Holes or chewed areas on leaves
- ** Leaves with webs or a white, sticky, or shiny substance on them
- ** Sap oozing from stems and branches
- ** Blackened, wilted or chewed stems
Disease organisms include fungi, bacteria and viruses. The most common disease problems found in this area are caused by fungi.
- ** Prevention is the best solution to these problems.
- ** Provide healthy growing conditions to encourage vigorous, healthy plant growth.
- ** Crowded plants trap moisture which encourages the growth of disease organisms. Proper plant spacing can be achieved by careful thinning.
- ** Move plants around in the garden. Although they are not moving far in such small plots, crop rotation still has some benefits for vegetable crops.
- ** Clean up the garden to remove materials which may harbor disease organisms.
- ** Purchase disease resistant plants. New varieties with resistance are constantly being added to the market.
- ** Avoid spreading disease. When handling diseased plants, clean tools and hands before handling other plants.
- ** Control can be difficult, so in most cases it is better to remove diseased plants and discard them where they will not spread disease organisms.
- ** If the problem is chronic or widespread, identification may be needed. Take samples to a nursery expert or extension office for help in identifying and treating the problem.
Weeds are a continual problem in any garden and are a common yard-care concern. To control weeds is to wage an ongoing battle. Besides detracting from the landscape's appearance, weeds may shade out desirable plants and take nutrients from them. Weeds can literally starve out other plants and reduce both the quality and quantity garden yields.
Weeds also aggressively use water. A water conservation tip: remove weeds from the vegetable gardens and flower beds so that less water is needed to grow desired plants.
Prevention is the easiest weed control. Give plants and seeds a head start on weeds by preparing weed-free seed beds and planting transplants and seeds during their ideal season with adequate fertilizer placed near the roots. These plants will grow quickly and can become established well ahead of the weeds.
Over watering perpetuates weed growth. Weeds grow best in moist, fertilized soil. Drip systems and fertilizer banding place water and needed nutrients where desirable plants can use them. Let weeds fend for themselves.
Layers of grass clippings, straw, twigs, and leaves smother many weed seedlings. Plastic is an excellent mulch. Black effectively controls perennial weeds but clear plastic encourages rapid vegetable growth. Clear plastic may need to be lifted once or twice during the summer to remove weeds that use it for a greenhouse, but the heat generated under the plastic in midsummer will burn off many seedling weeds.
Weeds are either annuals or perennials. Annuals only grow for one season, but they tend to produce seeds prolifically. Allowing them to mature aggravates the problem as they spread through the garden.
Weed plants enter surreptitiously, almost unnoticed, if a gardener is not paying close attention. They do not begin three feet tall, however. Pull seedling weeds in plant rows while they are small so they don't dislodge or damage the roots of other plants. The easiest time to dislodge weeds is after watering, while the soil is moist.
The best tools for weeding are hands, a hoe, and a cultivator. Be sure to remove the entire plant and root system of the weeds. Removing just the top does not kill the weeds. Remaining roots often send up another shoot.
Never underestimate the value of a hoe -- particularly when dealing with seedling weeds. Someone may or may not build a better mousetrap, but plenty of creative minds have gone to work improving on hoes. Hoes come in a wide range of designs from the old fashioned chopping blade attached to the end of a handle to a wide assortment of cutting blades set at various angles to slice off weeds below the soil surface.
Slicing types work by gliding the blade through the soil so it cuts off the plants below the ground. It isn't necessary to remove the entire root system provided the plant is cut off below the stem. The bigger weeds that sneak into less cultivated areas of the yard may need attention from a shovel or chopping hoe.
Never let weeds go to seed. An old garden saying is, "one year's seeds makes seven years' weeds." That assessment is on the right track but is not entirely accurate. Some seeds can lay dormant in the soil for 25 to 50 years and still sprout and produce a plant! But each weed removed before it goes to seed, removes the potential for hundreds or thousands more weeds to grow next season.
If weeds do take control, there are some very effective herbicides on the market. Use only when other measures are not effective. Pesticide use and recommendations for various areas are constantly changing. Check with your county agent for current recommendations.
Pay close attention to labels before purchasing these products. Labels will tell you which plants the chemical controls, which plants it does not harm, how to use them, and the length of residual effect. Timing is essential, too. Some products, such as 2,4-D, vaporize in hot weather and may damage other plants some distance away. Choose products that are compatible with the needs and goals of the garden.
Some herbicides are selective to certain types of plants. For example, fusillade, found in Grass-B-Gone® and similar formulas are formulated to control grasses around many ornamental plants. 2,4-D, found in a number of products, is effective to remove broad-leafed weeds from lawns and grassy areas.
Other herbicides, such as Surflan, Treflan, and Dacthal are effective in established plantings as weed barriers. PAY CLOSE ATTENTION TO LABELS. Some of these types of herbicides may damage certain types of plants, while others may not be safe on food crops. Some barriers have a long-term residual effect and may damage trees or other crops many years later.
Some perennial weeds such as quack grass, field bindweed (morning glory) and white top are very difficult to control without the use of herbicides. If an area is very seriously overrun with these weeds, it might be advantageous to postpone planting a vegetable garden and spend a season working on controlling them first. It is hard to treat difficult weeds with herbicides and avoid damage to nearby plants.
Covering the soil with plastic sheeting or heavy mulch for a whole season can help to kill these weeds. Herbicides can work well on certain problems but they are not selective killers so be extremely cautious in using them. They can also harm pets and people.
Glyphosate is a useful and fairly safe product found in various dilutions in Round-up® (40 percent), Knockout® (6.6 percent), Kleenup® (5 percent) and other brands. Glyphosate is non-selective which means it will kill nearly any green plant it touches. It is very effective on perennials. Placement is everything, but be sure to put it only on the plants you wish to control.
The best time to treat perennial weeds in vegetable gardens is after the frost kills the tomato vines. At that time, perennial weeds are metabolizing nutrients into their roots to maintain the plant through the winter. They carry the glyphosate into their roots along with the other nutrients where the glyphosate can work on them.
Difficult weeds get a lot of attention because they are so tough to get rid of. Herbicides are often required to control deep-rooted perennials. But the vast majority of intruders are annual weeds. The safest and most effective controls for them are cultural practices.
Consult a local nursery about specific problems you are having; take in a sample of the weeds and have them identified so you can determine the right course of action.