76 articles tagged "Insect and Mite Management".

Many of us may forget about the pesky squash vine borer until it’s too late. This pest of cucurbit crops tends to be sporadic in our region; you are either battling it every year or it hardly makes an appearance. The squash vine borer is a member of the clear-winged moths, a unique group of moths that are active during the daytime. They are very beautiful with their bright colored orange tufts on their legs (Figure 1), but can be devastating. The insect overwinters as a late instar larvae or pupa in the soil. When the weather warms, they mature and adults emerge. You can scout for the first generation of adults in the spring and should target pesticide applications at the base of the plant when adults are first spotted and for two weeks thereafter. If you wait, the eggs will hatch and the larvae will bore into the[Read More…]


Corn earworm moth numbers have been relatively low this season until recently, as numbers have exploded in pheromone traps. These moths will lay their eggs on numerous crops, with late-market sweet corn being particularly vulnerable at this time. Tomato and pepper growers should also be aware of the potential for earworm (also called fruitworm) damage, especially if these crops are surrounded by cornfields that are drying down  and are no longer attractive for egg laying.  


Several caterpillars in the ear can be very similar in appearance and habits, so identification to species of some of the worms in ears can be tricky. Note that, in general, you cannot use overall body color or damage for identification. Some identification tips, though not foolproof, appear below for the corn earworm, western bean cutworm, fall armyworm and European corn borer. We suggest you inspect cornfields soon before the larvae leave the ear and pupate.   This article was previously published in the Purdue Extension Pest & Crop Newsletter.


It’s not uncommon for us to get calls from growers who are expressing concern about a particular insecticide product that is not working as well as the growers would like. Often, growers will suggest that Product X is no good or that the target insect has now developed resistance to that particular insecticide. Before we jump to conclusions, we need to consider a number of possible causes for poor performance by an insecticide. Here are some questions to consider if you are not getting the control you would like. Are you using the right product? Every fall, a group of vegetable entomologists from throughout the Midwest thoroughly revise the insecticide recommendations in the Midwest Vegetable Production Guide (ID56). The products we list in the guide are the ones that we believe work for a particular pest, based either on research trials or through our experience with growers. That’s why we[Read More…]


Figure 3. Webbing produced on heavily infested cucumber leaves by two-spotted spider mite.

Despite the wet start to the summer that we are experiencing, we have some growers reporting spider mites in field watermelons (Figure 1). This pest is typically associated with hot, dry weather and can be especially problematic in crops grown under protection, such as in high tunnels. Spider mites often move into a field from an adjacent fencerow or rye strip. Two-spotted spider mites (Figure 2.) are most commonly a problem on watermelon and cucumbers in high tunnels, but also affect muskmelons. They can be detected by observing the yellowish discoloration on the upper side of the leaves or using a 10x hand lens and scouting on the underside of the leaf for the pest. Alternatively, you may use a white sheet of paper and tap the leaves above the paper to dislodge the mites; you will see them moving about on the sheet of paper. Because mites often migrate[Read More…]


Figure 1. A cucumber plant grown in a high tunnel died because of bacterial wilt.

Bacterial wilt is one of the most destructive diseases in high tunnel cucumber production. The reason bacterial wilt is so important is because, like other wilt diseases, it ties up with the entire vascular system of a plant, causing systemic effects (Figure 1). The relatively less important roles that other cucumber diseases play also make bacterial wilt the major limitation for high tunnel cucumber production in Indiana. For example, common cucumber diseases such as angular leaf spot, anthracnose and Alternaria leaf blight seldom occur in a high tunnel scenario; improved resistance to powdery mildew was observed in some of the newly developed cucumber varieties; downy mildew in general does not occur in Indiana until end of the high tunnel cucumber production season. The causal organism for bacterial wilt of cucumbers is Erwinia tracheiphila. After the bacteria enter the plant vascular system, it multiplies quickly. As a result, it interferes with[Read More…]


Figure 1. Seedcorn maggot in a melon stem

Three species of seed and root maggots attack vegetables in Indiana. The seedcorn maggot feeds on seeds and seedlings of sweet corn, cucurbits, lima and snap beans, peas, and other crops. Cabbage maggots can cause serious damage to transplants of cabbage, broccoli, cauliflower, and Brussels sprouts and make the fleshy roots of radishes, turnips, and rutabagas unmarketable. Onion maggots are pests of seedling onions, developing bulbs and onions intended for storage. Seedcorn maggot flies emerge in April and May and lay eggs preferentially in areas with decaying organic matter. Fields that are heavily manured or planted to a cover crop are more likely to have seedcorn maggot injury. Maggots burrow into the seed and feed within, often destroying the germ. The seeds fail to germinate and plants do not emerge from the soil, leaving gaps in the stand. When infested seeds germinate, the seedlings are weak and may die. Maggots[Read More…]


Figure 3. A cucumber beetle on the 0.7 x 1.0 mm screen (photo credit: John Obermeyer)

One of the most problematic insect pests that organic vegetable growers have to deal with is the striped cucumber beetle. The insect feeds on all the cucurbit crops, but can be particularly devastating to muskmelons and cucumbers because those two crops are susceptible to bacterial wilt of cucurbits, which is caused by a bacterium carried by the beetles. The only way to avoid this devastating disease is to prevent the beetles from feeding on the plants. There are no effective organic insecticides for managing striped cucumber so we have to look for alternative methods. Row Covers: Row covers can be used to physically prevent beetles from feeding on the plants. To be effective, these need to be placed over the plants immediately after transplanting or before direct seeded crops emerge. The edges of the row covers should be sealed with soil to prevent the beetles from crawling under the fabric[Read More…]


It’s that time of year, where we are prepping high tunnels and getting back into the full swing of production, slowly, here in the Midwest. Many of you have already begun to transplant and may have encountered your first pests on these new crops. Aphids are one that remain a problem in high tunnels, and may even have plagued your winter production (Figure 1,2,3). Some keys to preventing or controlling these pests rely first on sanitation and then careful scouting. Try to remove any green bridge material that may already be infested before transplanting into the space. This includes weeds, lingering winter crops or residues. Having a week without vegetative hosts should get rid of any overwintering residents. After transplanting scout diligently, at least weekly, or more often on susceptible young transplants. Aphid infestations tend to begin on the growing points or younger tissues of the plant. Be sure to[Read More…]


Figure 1. A pheromone trap in the field.

One way insects communicate with individuals of the same species is with pheromones. Pheromones are volatile chemicals released by an insect that usually can be detected only by individuals of the same species. There are a number of different types of pheromones, but the most common type is the sex pheromone. Usually the females will emit a tiny amount of a chemical that attracts the male to her and increases the likelihood of mating. Because the chemical is volatile, air currents carry it. The male detects the pheromone in the air with receptors on his antennae. He then flies upwind to find the source of the pheromone, a prospective mate. The chemical compositions of pheromones for a number of pest species have been identified and synthetic copies can be produced in the laboratory. Synthetic pheromones can be used in conjunction with traps to catch male insects. Listed below are some,[Read More…]


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