Category Archives: Weed/Pest Control

Pests in the Garden: Cabbage Maggot

Final Installment

CABBAGE MAGGOT

Cabbage Maggot

One of the most destructive early season pests of crucifers and certain root crops in NH. It can cause severe injury to cabbage, cauliflower, broccoli, Brussels sprouts, radish, turnip, rutabaga, beets and celery if not controlled.

Description
The adult fly is similar in appearance to the common house fly, but smaller (1/4-inch long). It is dark, ashy gray with black stripes on the thorax and black bristles over the body. In the spring, female flies are commonly seen flying close to the ground, depositing small white eggs in cracks and crevices near the stems of host plants.

Larvae destroy plant roots by their tunneling habit. This will often cause young cabbage, broccoli and cauliflower seedlings to wilt and die. Plants like radish and turnip become scored with feeding trails, making them susceptible to attack by disease organisms.

There are typically 3 or 4 generations of CM each growing season in New Hampshire.

Prevention and non-chemical control
Cover cabbage family transplants or newly-seeded rows with floating row covers until June 1, or delay planting until then to foil the first generation of egg-laying cabbage maggot flies. Alternatively, protect cabbage, broccoli, cauliflower and other cole crop transplants with barriers made by punching a hole in the center of a six-inch square of tarpaper and slitting the paper from one corner to the center hole. Then place the tarpaper square flat on the ground, with center hole snugly encircling the stem of the transplant.

Bottom Line for Pest Control….
OBSERVE! 
Use floating row covers to minimize heavy infestations.  Squish or dispose of pests in container of soapy water.  Dispose of garden debris.  Mow your borders and dispose of standing weeds.  If your soil is strong, your plants will be strong and able to withstand some assaults—the plants may be a little ragged for a bit but they can recover!  And remember—this is supposed to be FUN!

Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!

ACKNOWLEDGMENTS: 
The information above was gleaned from the UNH Cooperative Extension Website  a GREAT resource!


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Pests in the Garden: Wireworms

Installment #8

WIREWORMS

Wireworms

Wireworms damage root and tuber crops such as potatoes and carrots by tunneling, causing unsightly holes as well as providing an entry point for pathogens. Young seedlings with small root systems can be weakened or killed.
Wireworms are the larvae of click beetles (family Elateridae). There are many species of wire­worm. The larvae have slender, hard, ¾ -2 inch long bodies that range from tan to orange to brown in color. The larvae pupate in the spring, and the adult beetles emerge and are active in the summer. The adult beetles are not typically pests. Female click beetles lay eggs during May and June. They lay eggs in the soil, primarily in weedy or grassy fields. The eggs hatch in 3-4 weeks, and the larvae then look for food. The larvae can live for several years, depending on the species, availability of food, temperature, and soil moisture. Because eggs are typically laid in grassy fields, wireworm problems are usually most severe in fields that were recently sod. However, because the larvae can live for several years, problems can persist in fields that have not been sod for some time. And grassy cover crops can attract adults for egg laying. Wire­worms are often more prevalent in moist areas of fields, and in areas with high organic matter.

What they Eat.
Wireworms are omnivores. They feed on the roots of grasses or weeds and on other soil insects. It is hard to starve wireworms out of a particular area, because of their diverse diet. Crops that tend to increase wireworm popula­tions include potato, carrot, sweet potato, small grains (wheat, barley), onion, beet, and clovers. A clean (non-weedy) alfalfa crop can reduce populations. This may be in part because of alfalfa’s deep root system reduces soil moisture, making the environment less favorable for the larvae.

Minimizing Damage.
Rotation into alfalfa or crops that are not preferred can reduce wireworm populations. Avoid plant­ing highly susceptible crops such as potato and carrots into sites with a high potential for damage, such as fields previous­ly planted to grass sod, pasture or small grains, or fields with a prior history of wireworms. The edges of fields (near sod) can also be a problem, because the larvae can move through the soil in search of food. Baits can be used to determine wireworm pressure prior to planting a susceptible crop. This can be done by placing carrots or potatoes in a softball-sized hole about 4-6” deep, covering with loose soil, and then covering the area with a piece of black plastic to warm the soil. Wait 4-7 days, and dig up the bait to check for the presence of wireworms before planting. Another version of this method involves burying a fist-sized clump of corn, wheat, or rolled oats. It may also help to harvest crops as soon as possible. Moisture in potato tubers if soil conditions become dry, and wireworm damage increases over time in potato crops left in the ground.

Chemical Control.
Insecticides used to control wireworms are applied preventatively to the soil, either by broadcast­ing before planting, at the time of planting in the furrow, or as seed treatments

Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!

ACKNOWLEDGMENTS: 
The information above was gleaned from the UNH Cooperative Extension Website  a GREAT resource!

Pests in the Garden: Squash Vine Borer

Installment #7

SQUASH VINE BORER

Squash Vine Borer

Begin monitoring your squash plants for the adults, moths that look like black-and-red wasps with metallic forewings. They lay eggs in the soil at the base of squash vines (both winter and summer varieties). The larvae soon hatch and bore holes near the base of the vine. Routine inspection of your plants may reveal a small pile of yellowish-green sawdust-y frass where the vine meets the soil, indicating the point of entry. Larvae gradually eat the inside of the stem, occasionally leaving deposits of frass where they have punctured through the vine wall. Sometime the frass is found oozing from the stem. The borer may even invade developing fruit. Naturally, the vine is weakened and succumbs, either from an inability to absorb water and nutrients or by secondary disease.
Protective sprays with products licensed for squash borer will achieve the best control of this pest. Products containing spinosad, derived from a naturally occurring bacterium, have a low toxicity to non-target organisms. Spray according to directions, making sure the spray penetrates the leaf canopy to coved the stems all the way to the base of each plant. With any pesticide, follow label directions explicitly.

You may achieve some control by carefully splitting the vine lengthwise with a very sharp blade at the point where you see frass, cutting as short a span as possible. Locate and remove the invader, or prick it with a needle or other thin, sharp tool. Gently close the cut and mound soil around it. In many cases the plant can be saved. Be sure to destroy the vines at the end of the season, taking care to remove as much of the vine as possible below the soil line.

Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!

ACKNOWLEDGMENTS: 
The information above was gleaned from the UNH Cooperative Extension Website  a GREAT resource!

Pests in the Garden: Squash Bugs

Installment #6

SQUASH BUGS

Squash Bug

The squash bug, Anasa tristis, is common throughout the United States. The squash bug will attack all members of the cucurbit family but are most common on pumpkins and squash. Feeding, via piercing/sucking mouthparts, occurs primarily on the plant foliage. However, late in the season, squash bugs may also feed on fruit. The associated damage symptoms include wilting of leaves and ultimately results in leaves that appear black or dried out.

The squash bug can be misidentified as a stinkbug. Both insects look similar and emit a distinct odor when crushed; however, the stinkbug is not a pest of cucurbits and is more commonly associated with tomatoes or various legumes such as soybeans and peas.

Squash bug adults are 5/8 in. long and 1/3 as wide. They are usually gray to black with the edges of the abdomen having orange and brown stripes. Nymphs are 3/16 to 1/2 in. in length. Young nymphs have a red head and legs with a green abdomen, however as the nymphs age the red color will turn to black. Late instar nymphs will be greenish-gray in color with black appendages.
Eggs are 1/16 in. long and have a yellowish brown to brick red color. Eggs are laid individually in groups of about twelve on the underside of leaves. Each cluster of eggs is usually laid in a characteristic V shape pattern following the leaf veins. Eggs are laid under the leaves from spring to midsummer and will take 1-2 weeks to hatch. The eggs will become darker as they get close to hatching.
Squash bugs feed on cucurbits (vine crops) and prefer squash and pumpkin. Both adults and nymphs cause damage by sucking nutrients from leaves and disrupting the flow of water and nutrients, which can cause wilting. Initially, before wilting, yellow specks will develop on the foliage that eventually turn brown. Under heavy feeding pressure, small plants can be killed; larger plants can have many affected leaves and vines. Subsequent wilting can look similar to bacterial wilt; however, bacterial wilt is a disease spread by striped cucumber beetles and is much more detrimental. Once the squash bug population is reduced, wilted plants should recover. By contrast, plants infected with bacterial wilt will continue to decline and will eventually die. Therefore, it is important to determine which wilt is occurring, and the correct identification of the insect pests present in the field is an essential first step. Squash bugs will also feed directly on the fruit, and it has become an increasing problem in recent years.

The adult squash bug is difficult to kill, so early detection of nymphs is important. The smaller the insect, the easier it is to control. Threshold is reached when the average number of egg masses (meaning groups of eggs) is greater then one egg mass per plant. Control measures should be taken when the threshold is reached or when wilting occurs and the damage is attributed to squash bug and not other pests or environmental conditions. Seedlings, new transplants, and flowering plants are the most critical growth stages to monitor, as these are the stages when the most damage can occur.

Organic Control
There are few if any effective organic control options for squash bug. However, natural enemies of the squash bug include Tachinid fly, Trishopoda pennipes and Sceleonids, Eumicrosoma spp. These biological control options may prove useful. Sabadilla may provide some control and is organic certified
If only a few plants are affected, it is most effective to hand pick and destroy squash bugs and eggs. Another option is to place boards or shingles on the ground next to the plants. At night the squash bugs will aggregate under the boards and can then be destroyed each morning. Using resistant varieties such as Butternut, Royal Acorn, or Sweet Cheese and maintaining a healthy plant through proper fertilization and watering are also important to limiting squash bug damage. It is also necessary to remove debris in and around the garden area that could possibly be used as shelter by the bugs. As stated above, by removing debris from the area, overwintering sites for the adults are reduced. Sevin is one of the few insecticides available to home gardeners.

Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!

ACKNOWLEDGMENTS: 
The information above was gleaned from the UNH Cooperative Extension Website  a GREAT resource!

Pests in the Garden- Flea Beetles

Installment #5

FLEA BEETLES

Flea Beetle

The name flea beetle describes many species of small beetles that chew tiny shot-holes in plant foliage and jump around like fleas when disturbed. Although some species feed on a wide range of plants, most FB species attack a single species or family of related plants.

Flea Beetle Damage

New Hampshire garden crops most likely to suffer early-season FB attack include cabbage-family crops, potatoes, tomatoes, eggplant, beets, corn, grapes and spinach.

FB damage is worst in spring. Heavy infestations can kill an entire planting of newly-germinated seedlings or severely weaken young transplants. FB damage also renders plants vulnerable to attack by pathogens; in some cases, the beetles actually transmit disease such as early blight of potatoes. Larvae of most FB species feed on the roots of the same plants being attacked from above by adults. Other FB larvae mine leaves or feed on underground stems.

Adult FB are small, elongate-oval beetles, typically between 1/16” (potato FB) and 1/5” (grape FB) long, with narrow prothorax and head. Most species are black, brown or another dark color; some with striped wing covers.

Prevention and non-chemical control
Since adult FB feed on weeds in the early spring and late fall and FB larvae may be present in large numbers on weed roots, controlling weeds in and around the garden will go a long way towards control­ling this pest.  Providing the gardener has paid rigorous attention to crop rotation and fall garden cleanup (depriving adult FB of overwintering habitat in the garden), floating row covers will offer excellent protection for direct-seeded crops and new transplants.

Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!

ACKNOWLEDGMENTS: 
The information above was gleaned from the UNH Cooperative Extension Website  a GREAT resource!

Pests in the Garden-Striped Cucumber Beetle

Installment #4

STRIPED CUCUMBER BEETLE

Striped Cucumber Beetle

The Striped Cucumber Beetle (SCB), Acalymma vittattum (Fab.), is one of the most devastating pests of cucurbits (cucumbers, summer and winter squashes, all types of melons and pumpkins) east of the Rocky Mountains. Both adults and larvae feed on cucurbit crops. This insect is also responsible for the spread of plant diseases such as bacterial wilt and cucumber mosaic. Cantaloupe and muskmelons are especially vulnerable to bacterial wilt spread by the beetles.

Description
The adult beetle is 1/4 inch long and yellow-green in color with black longitudinal stripes. Eggs are small and orange-to-yellow in color. The worm-like larva is slender, white, and about 1/3 inch long when full-grown.

Life Cycle
The Striped Cucumber Beetle overwinters as an unmated adult in the neighboring areas of old cucurbit patches, under fallen leaves, in hedgerows, near their wild food sources (goldenrod, aster) and in gar­den debris. The adults emerge in the early spring before cucurbits are available as food, feeding on pollen, petals, and leaves of alternative hosts.

Depending on geographic region and weather conditions, New Hampshire gardens may experience one, two or even three generations of CB in any given season.

Striped Cucumber Beetle Damage

Prevention and non-chemical control
Rotate cucurbit crops to a new place in the garden each year. Deprive adult beetles of homes for over­wintering by removing crop residues and alternative host plants such as asters and goldenrod from around the garden.

Do not use insecticides while cucurbit crops are in bloom. Most insecticides are hazardous to bees. An exception is Surround, which doesn’t kill insects, but instead is designed to plug up taste and smell receptors that pests use to confirm identity of plants before feeding on them. In some areas striped cu­cumber beetle has become resistant to chemical insecticides

Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!

ACKNOWLEDGMENTS: 
The information above was gleaned from the UNH Cooperative Extension Website  a GREAT resource!

Pests in the Garden-Cutworms

Installment #3

CUTWORMS

Cutworm

Cutworms are the larval form of dozens of different species of small brown or tan, banded moths. Depending on the species, cutworms damage plants in several ways:

1.) Surface cutworms chew plants just above or just below the soil level, typically eating just enough of the stem to make the plant topple over, but occasionally dragging plants or plant parts down into their borrows.

Cutworm Damage

2.) Climbing cutworms climb the stems of herbaceous plants, shrubs, vines and trees, feeding on buds, stems, leaves and fruits.
3.) Army cutworms occur in great numbers and, after consuming the vegetation in one area, migrate by the thousands onto adjacent land. Army cutworms feed mainly from the tops of plants, but in large enough numbers, will consume entire plants.
4.) Subterranean cutworms remain in the soil and feed on roots and the underground parts of stems.

Description
The adults of all cutworm species are night-flying moths with wing-spans from 1-1/2 to 3 inches. Only the larvae damage plants: adult moths feed off the nectar of wild and cultivated flowers. Full-grown larvae are 1-2 inches long, soft, plump, hairless cater­pillars whose color and markings vary from dingy white to tan, brown, charcoal gray or black, depending on species. A disturbed cutworm will curl up into a tight ball.

Prevention and non-chemical control
To determine if cutworms are present, look for signs of freshly cut plants. Take a flashlight at night to search the base of the plant and the top layer of soil for cutworms. Handpick any cutworms you find and squash them or drown them in a bucket of soapy water.

Since adult female moths lay their eggs during the fall, removing weeds and mowing the grass close to the ground will aid in prevention of cutworm infestation.

A protective collar made of plastic, sturdy cardboard, cut-up drink bottles, milk cartons, toilet paper rolls, etc., will protect transplants against cutworms. Place the collar around the plant stem, making sure it extends at least an inch down into the soil and two inches above soil level

Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!

ACKNOWLEDGMENTS: 
The information above was gleaned from the UNH Cooperative Extension Website  a GREAT resource!