Rick Foster

Professor
Department of ​Entomology
Area(s) of Interest: Pest Mgmt. Vegetable and Fruit Crops
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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.


(Photo by John Obermeyer.)

​Fall armyworms have completed their annual trek from the Gulf Coast to the Midwest. Fall armyworm larvae will feed on all aboveground parts of the sweet corn plant, during all stages of growth. The damage to the foliage is much more severe than with European corn borer. Larvae will feed from within the whorl of the plant until the tassel starts to emerge, at which time they will move to other plant parts, including the ear. Larvae will enter the ear either through the tip, similar to corn earworm, or they may come through the husk into the side of the ear. The best time to control fall armyworms is during the late whorl stage, before they tassel emerges and they start to move. Pyrethroid insecticides such as Warrior®, Brigade®, Mustang Max® and Hero® will provide excellent control. Most growers will want to save their more expensive Coragen® or Radiant® treatments for earworm control[Read More…]


(Photo by John Obermeyer.)

​I have seen more green stink bugs this year than at any time in my career. I have no logical explanation for their abundance. It was thought that as the invasive brown marmorated stink bug became established, it might outcompete the native stink bugs such as the green stink bug, causing numbers to decrease. However, this year, brown marmorated stink bugs have been relatively uncommon, and green stink bugs seem to be everywhere. Stink bugs feed with their sucking mouthparts and are likely to feed on a wide variety of vegetable crops, including cabbage, sweet corn, cucumber, bean of all types, okra, mustard, peas, peppers, and tomato. Check the Midwest Vegetable Production Guide (ID-56) for your particular crop for insecticide recommendations.


​Growers should remember as of July 31, 2015, it is illegal to use endosulfan on any crop other than pineapple or strawberry. By July 31, 2016, all use of this product will be cancelled. Endosulfan in an organochlorine insecticide, the same class as DDT, and was first produced in the US in 1954. It has been a very effective insecticide for over 60 years, but is quite toxic to humans, so it has outlived its usefulness. Fortunately, we have a variety of newer, safer products available today.


​Yellowstriped armyworms continue to cause problems for tomato growers, especially in high tunnels. The populations are often spotty within a field or high tunnel, but can easily reach damaging levels. Most of the insecticides listed in the Midwest Vegetable Production Guide for control of caterpillars on fruiting vegetables (pages 135-6) will control yellowstriped armyworms. If spraying within a high tunnel, be sure that the label allows use in a greenhouse or high tunnel. Consult Table 16 on page 40 for available options.


​In years past, the European corn borer was the most important pest of sweet corn, as well as being a pest of peppers and other vegetables. Since the advent of Bt field corn, the overall population of corn borers has been dramatically suppressed, so far that we often forget about it being a pest of sweet corn. However, occasionally the corn borers like to remind us that they are still around and can still be damaging to our crops. These outbreaks usually occur in the northern part of the state, often in areas where the landscape is not dominated quite as much with field corn and soybeans. Corn borers have a broad host range, so diverse habitats provide them with a choice of suitable foods. Management of corn borers in sweet corn is relatively easy. As your sweet corn approaches tasseling, look for corn borer feeding and confirm that borers[Read More…]