102 articles tagged "Insect and Mite Management".

Figure 1. Striped cucumber beetles on melon plants

We found our first striped cucumber beetle on Friday, May 20 and several more on May 23 (Figure 1). Given the cool weather, this is a little earlier than we would have expected. As the temperatures warm up this week, it would not be surprising for cucumber beetles to become very numerous in our melon and squash fields. Striped cucumber beetles are more attracted to squash so growers with those crops should look there first to see if the beetles are active in their area. Growers who direct seeded crops treated with FarMore® insecticide can expect about 3 weeks of control of striped cucumber beetles from that treatment. Growers who grow transplants from seeds treated with FarMore® will receive no benefit from those treatments once plants are in the field because the 3 weeks of control have ended. Likewise, growers who treated at planting with Platinum® or Admire Pro® can[Read More…]


Figure 1. Flea beetles on Brassica (photo credit: John Obermeyer)

Many of our vegetable crops are subject to feeding by one or more species of flea beetles (Figure 1). Flea beetles get their name because they have enlarged hind legs that allow them to jump like fleas. Most species are quite small, and with their ability to jump, often seem to just disappear when disturbed. Flea beetles tend to feed on the leaves, chewing small round holes. When populations are high, the feeding holes with overlap, creating larger holes. Flea beetles tend to be early season pests, primarily because smaller plants are more affected by their feeding. Treatment thresholds vary from crop to crop. For example, eggplants, on of the most commonly damaged vegetable crops, should be treated when there is an average of 4 beetles per plant. For tomato, the threshold is when leaves are 30% defoliated. Crucifers have no particular threshold, so treatment should be made when leaves[Read More…]


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I caught my first earworm (Figure 1) moth in a pheromone trap last week. Earworms are very polyphagous, meaning they will eat lots of different plants. I suspect that any females that are flying are laying their eggs on wild plants of some sort and not on the seedling stage sweet corn or dent corn that is present in fields around the state. If you are one of the aggressive growers who grows sweet corn in the greenhouse and transplants it to the field to get that early market, your plants (unless they are covered by row cover) may be subject to earworm egg laying and feeding. This generation of larvae will be long gone before ears begin to form, so your only concern will be the foliar feeding damage and not ear infestation.


The cool, wet weather we are experiencing is perfect for the root and seed maggots, namely cabbage maggot, onion maggot, and seedcorn maggot. One way of avoiding damage from these pests is to wait until the soils warm up to 70o F before planting, but that is not always possible. The use of row covers early in the season can physically prevent the flies from being able to lay their eggs on the soil near the base of the plants. There are some insecticides available, which vary by crop. Lorsban®, for the crops on which it is labeled, is probably the most consistent of the available insecticides. Capture LFR® has shown decent efficacy on melons and other crops. Melon growers who are putting Admire Pro® or Platinum® on as a soil drench at planting should not expect any control of seedcorn maggots from those applications.


Three species of seed and root maggots attack vegetables in Indiana. The seedcorn maggot (Figure 1) feeds on seeds and seedlings of sweetcorn, 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.[Read More…]


In recent years, many seed companies have begun using the neonicotinoid insecticide thiamethoxam (FarMore) as a seed treatment on cucurbit and other vegetable seeds. Thiamethoxam is a systemic insecticide that moves from the seed coat into the seedling and then moves throughout the plant. Research has shown that these seed treatments provide about 3 weeks of excellent control of cucumber beetles, aphids and other pests. Unfortunately, the systemic nature of the insecticide also results in residues being present in the pollen that could potentially be harmful to honey bees and other pollinators. Although these seed treatments are a good pest management tool, growers should be cautious in how they use them to avoid possible harm to pollinators. Our research has shown that cucurbits that are grown in the greenhouse for 4-5 weeks before being transplanted into the field, do not have enough of the insecticide left in the stem and[Read More…]


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, but[Read More…]


​Catches of corn earworm moths in pheromone traps are gradually increasing. I had 18 in my trap this morning (August 18). The gradual increase is indicative of the local population emerging. We can expect them to continue to gradually increase for most of the remainder of the season. What we have not had is the massive influx of moths from the south, likely due to the lack of tropical storms in the Gulf of Mexico and few storm fronts coming northward from the Gulf States. With populations as they are currently, most sweet corn growers should have little problem managing this pest. A regular spray program should provide nearly perfect control. There are three main factors that you have control of that determine the level of control you will receive. You need to have the right chemical in the right place at the right time. I recommend using Coragen® and[Read More…]


(Photo by Dan Egel)

​We have received a number of reports of outbreaks of spider mites, primarily in watermelons and in high tunnels. The problems in high tunnels are not unexpected because one of the primary causes of mortality in mite populations is rainfall washing them off the plants and, of course, that is lacking completely in high tunnels. With all the rain we have had, it’s a little surprising that we are seeing problems in watermelons, but the older I get, the less I’m surprised by how infrequently arthropods behave the way we expect them to. In both scenarios, we don’t really have treatment thresholds for mites. Generally speaking, if populations are increasing, they need to be controlled. Once the decision to treat has been made, that’s where things get very different. In watermelons, we have a variety of pesticide choices. See page 115 of the Midwest Vegetable Production Guide (ID56) for the[Read More…]


​Pheromone trap catches for corn earworms continue to be very low. Again, this is a time when growers can save a lot of money and time by monitoring their pheromone traps and not spraying. I harvested untreated sweet corn on Friday, July 31, and had over 98% clean ears and the few that were damaged had very few kernels fed upon and in 400 ears, we found not a single earworm. On the other hand, moth flights are likely to pick up any time between now and about August 20, based on 28 years that I have been monitoring their flights in Indiana. Regularly checking your moth catches will help you to know when the moths have arrived and when you need to increase your management activities. The treatment threshold now is 10 moths per night, because of the maturity level of field corn nearby.


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