A Listing of Other Plant Pests: A-E

Ants

Ant herding aphids

In people’s homes certain species of ants can be a problem, and this is well known. Carpenter ants — though not wood-eaters — do make galleries in structural wood and can make an otherwise usable house into an unsafe structure by weakening the wooden members. Many sugar-eating ants, including carpenter ants, can be nuisance pests as they forage in kitchens, bathrooms and other suitable rooms in their never-ending search for food. Moreover, they can spread harmful bacteria. This is also true of protein-eating ants, which may also bite you. And, speaking of biting, southern fire ants can be a real pain — literally.

Ant on leaf

Homopteran pests like aphids, whiteflies, mealybugs and soft-scale insects, all produce a sugary, liquid feces-commonly called honeydew-which many ants just love. They love it so much, in fact, that they’ll hang out with these pests, protecting them from many predacious and parasitic biocontrol agents. In this sense, ants can degrade the efficacy of a biocontrol program as ants may deny biocontrols access to their prey or hosts. These same ants will sometimes physically help in the spread of these pests as the plants they’re on begin to weaken, or as their demand for honeydew grows. There are chemicals which are effective for controlling ants, but being that you’re reading about the Green Methods, most of those chemicals are unsuitable. Boric acid baits are available as gels, pastes, powders and liquid feeding stations. They are the safest, most environmentally reasonable way of dealing with these pests — unless you can effectively bar their passage with barrier-type products such as diatomaceous earth or simple caulking. Boric acid baits are designed to take out the problem at its source as the bait is supposed to be brought back to the colony’s queen and brood.

Apple Maggots

If you grow apples, apple maggots will become a part of your life. Period. And spraying is how most apple growers cope with these pests. And this is understandable as apples are extremely difficult to grow using non-chemical means. It can be done, but if you try you’ll probably be running a cider- and apple by-product-heavy operation as good, unblemished picking apples will be fewer and further between and “drops” will be common. There’s nothing wrong with many of the apples which won’t pass muster, but try convincing consumers of this. Apple maggots are 6-8 millimeter flies with clear but patterned wings which lay their eggs in small punctures in the skin of apples. The flies’ eggs hatch and the resulting larvae tunnel their way through the meat of the fruit until the apples drop to the ground. The larvae then leave the fruit preferring the shelter of the ground to pupate. Conventional growers place a few red spheres — which are coated with a sticky substance — in their trees to capture the flies so they know when to spray. Organic and unconventional growers place many of these spheres in their trees in hopes of not only monitoring the situation, but to capture enough of these flies to reduce the over all population and, thus, the damage they cause. This is sound thinking. Additional controls include the use of repellent products such a garlic sprays, neem-based products (which can repel pests if applied heavily), apple maggot control bags, and Kaolin or China clay. Other techniques include removing and destroying, or utilizing, dropped fruits before the larvae exit the apples. Parasitic Nematodes are also a good control measure against the larvae as they dwell in the soil and exploit the pupae. Multiple applications would be necessary for the purposes of timing, but it is not critical as some of the pupae stay in the soil more than one season. Other potential tactics include planting cover crops around trees in hopes of sheltering ground beetles which may prey on them.

Armyworms

These are larvae of unremarkable-looking grayish-brown moths. The moths are about three centimeters and can be distinguished by a white dot on each wing-but that’s only if they are seen, which is unlikely for they are nocturnal. The worms or larvae are up to four centimeters long and striated with green, brown and whitish stripes running lengthwise along their plump bodies. The, worms, too, are nocturnal, and will probably not be seen chowing down on corn and other field and garden crops-and the damage will look like something was “chowing down.” Armyworms are found in forms varied from what we’ve described, and some show preferences to specific crops: beets, for example. A common characteristic, though, is their flair for feeding. Consumed parts may include leaves, stems, roots and tubers, and even the fruiting bodies themselves. Parasitic Nematodes can play a role in the control of these pests. They overwinter as larvae (or pupae, depending on species). Thus early to late spring or late summer to early fall may be a good time to attempt a nematode offensive. However, anytime armyworms are found as larvae in or near the soil will work. Bacillus thuringiensis (Bt) variety Kurstaki will also control these pests. When these worms bravely venture out at night to feed on upper plant portions, you’ll nail them with Bt-K. A last option would be to use a row cover to keep adults from laying eggs on the plants.

Bagworms

Moths! What a pain. These two centimeter long clear-winged black moths mate with wingless black females which lay their eggs on shrubs and trees in little “bags” made of leaves or pine needles. The larvae which hatch from the eggs venture forth, feeding as they go, eventually making new bags of their own in which to settle down and eventually complete metamorphosis. They grow to about two centimeters, enlarging the bags as needed along the way. Bacillus thuringiensis (Bt) variety Kurstaki can be used effectively against these pests if the larvae are targeted early in the season, before they become bagworms in the formal sense. As far as we know, the most effective method of ultimately controlling these pests is to get out there and physically remove the bags by cutting the silk which secures them to the twigs. (If the silk remains it can girdle a twig.) As another option, there are commercially available traps for capturing the flying male adults very late in the season. The traps used are pheromone or sex traps-they smell like girl bagworm moths.

Black Vine Weevils

Black vine weevil adult

These insects are major pests of many ornamental nursery crops. Some greenhouse crops fall victim to these pests, too-though this is atypical. Their feeding causes a distinctive notching of leaves when they are adults. As larvae, residing in the soil, they feed on roots. In either case they are not a welcome sight, even though they are seldom seem. Their feeding damage, however, isn’t likely to go unnoticed. Black vine weevils are fairly tough-looking robust insects approaching nine millimeters as adults and may be found during the day hiding out in sheltering debris, leaf litter, etc. In greenhouses they can sometimes be captured on sticky traps placed sticky-side-up on the ground. Better yet, though, for scouting, is to design harborages for them which can be quickly uncovered during the day. Parasitic Nematodes are a good method of controlling the larval and pupal stages of these insects. One university trial determined nematodes, when compared to the big-gun chemicals available, are one of the best controls for these pests.

Cabbage Maggots

Cabbage maggot adult

You may think these inconspicuous fly-looking flies buzzing around your brassica or cole crops (cabbage-family plants) are not-a-problem, but think again. These little flies could be busy laying eggs in the soil at the bases of your plants in the spring and beyond. That is if they’re cabbage maggot flies. The eggs the flies lay hatch into white maggots which grow to seven millimeters-the same size in which they’ll be as adults. These larval maggots tunnel into the roots of the cabbage-family plants, where they can cause extensive physical damage and various root rots. Covering cole crops with a row cover will keep flies out of your plants. But a row cover might keep things too hot for these crops — they like it cooler. Moreover, if the flies’ pupae are in the soil already, the row cover will keep them in when they emerge in the spring. Parasitic Nematodes are an excellent option for the control of these pests. They’ll love those little maggots. A sheet made of black plastic or some other impenetrable and opaque material covering the ground around the plants works well to keep the flies laying eggs elsewhere. The plants will grow through slits in the plastic. It will also serve to keep the moisture in the soil. Other products may also help. Capsicum pepper wax or garlic products sprayed on the ground and lower plants portions may deter the flies.

Carrot Beetles

With many beetles it is the larval stage which is damaging to plants-especially when that damage occurs below ground-but with this species, it is the large red-brown beetles at fifteen millimeters adults which tunnels into the roots of carrot and other crops. The C-shaped larval grubs, which grow 25 mm., are in the soil, too, but tend to feed on grasses more than they feed on carrots. Parasitic Nematodes are a viable means of control, as long as your timing is right and you focus on a wide-ranging area around where your carrot crop is planted-including areas where there is grass or leafy debris.

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