85 articles tagged "Insect and Mite Management".

Fig. 1 Corn earworm adult on silk. Photo courtesy John Obermeyer.

We have begun our state-wide trapping and monitoring program for corn earworm (Figure 1). The latest trap catch information can be found here. Traps have been placed at each of the eight Purdue Agricultural Centers throughout the state. Trap catches at the reporting farms are already in the double digits. Please refer to E-31 to learn more about corn earworm identification and management. Management and insecticide sprays target the eggs that are laid, preferably on fresh corn silk. If no field corn in the area is silking, which is true for most this year, use a threshold of 1-3 moths per night per pheromone trap. You only need to spray your sweet corn if it has silk present. When field corn begins to silk and green silk is present the threshold increases to 10 moths per night. Eggs are laid individually on developing silk. They hatch within 2-5 days and[Read More…]


Figure 2. Yellow striped army worm feed on strawberry fruit.

At the Southwest Purdue Ag Center, we are studying annual strawberry production on plastic mulch. Our hope is to gather information for best production practices in our area. As we learn about insect and disease problems, we will pass this information on to producers. This article is about the insect pests we have observed in our strawberries that were planted in March 2019. Armyworm– Toward the end of the spring harvest, we observed significant damage on strawberry fruit caused by armyworms. Beet armyworm and yellowstriped armyworm larvae were found in the field (Figure 1 and 2).  They feed on both green and ripe strawberries. More than 30% fruit became unmarketable because of the insect feeding. Damage was also observed on flowers. Armyworms also cause significant damage when they chew on strawberry crowns and leaves of summer-planted young strawberry plants. Midwest Fruit Pest Management Guide provides several options for controlling the[Read More…]


Figure 3. Cucumber cultivar Taurus were grown in the front, cultivar Corinto was grown in the back.

Supported by NC SARE (LNC17-390), we are continuing research for improving high tunnel cucumber production. One of the biggest challenges for growing cucumbers in high tunnels in the summer is two-spotted spider mites. Dry and hot environments featured in high tunnels allow two-spotted spider mite populations to increase rapidly. The mites cause leaf yellowing, necrosis, and defoliation that interfere with plant photosynthesis. Yield can be significantly reduced. The pest also causes direct damage on cucumber fruit, resulting in a sandpaper-like texture to the rind (Figure 1). Early detection is the key for controlling two-spotted spider mites. As soon as two-spotted spider mites are detected, control efforts need to be taken. In the early stage, yellowish specks on the upper side of the leaves may be noticed (Figure 2). Turn the leaf over, on the other side of where the yellow specks are, you may find the presence of two-spotted spider[Read More…]


Figure 1: A cantaloupe plant surrounded by striped cucumber beetles that have died after feeding on a plant treated with an imidacloprid product.

I know this may not come as a surprise to most of you, but it is rare that we get to observe the effectiveness of insecticides in such a dramatic way as we encountered when visiting a melon grower in southern IN recently. And in this case, the decision to apply an insecticide at transplant was a good one. In the photo below (Figure 1), one can see an accumulation of dead striped cucumber beetles that have fed upon a cantaloupe seedling that was treated with an imidacloprid soil drench (Trade names include: Admire Pro®, Macho®, Midashe Forte®, Montana®) at transplant 14 days prior to the photo being taken. The beetles are dead because they fed upon the cantaloupe plant and ingested the imidacloprid. Therefore, the plants were protected from defoliation by the beetles, but what about bacterial wilt? Did the act of feeding, however brief, cause bacterial wilt to[Read More…]


Seed Corn Maggot in cucurbit stem. Photo credit John Obermeyer.

In addition to delaying much of our fieldwork, the cool set spring has wreaked havoc on some of the plants we have been able to squeeze in during brief dry periods. We have received reports of damage caused by seedcorn maggots (Figure 1) and wireworms (Figure 2). In preparation of this article I browsed the Vegetable Crops Hotline archives and came across eight articles published by Rick Foster. What do they have in common? Associations with weather and limited strategies for control. Capture LFR® remains the only product labeled and for wireworms only. Rick Foster did some work with this product and had some promising results. Seedcorn maggots typically lay their eggs in organic matter and feed on seed in the soil, however, they can also cause damage in cucurbit transplants. The adults are active in April and May laying eggs in the field. When soil temperatures reach 70°F the[Read More…]


As we wait patiently for the ground to dry and our seedlings to grow, take a moment to consider your strategy for maintaining plant health. If you haven’t started already, it is time to make sure that your pest monitoring programs are in place for the season. For those of you growing in high tunnels, you may already be encountering some of the troublesome insects that can keep us up at night, such as aphids and spider mites. Here, I want to review some basic considerations for monitoring and detecting insect pests. First, it is important to recognize that the best way to avoid insect damage is prevention. This includes sanitation practices and monitoring of transplants. Regardless of your production method (greenhouse, high tunnel, field) you want to be sure that any plants that have overwintered in the area free from overwintering pests. This can include disease residue on plant[Read More…]


Great information on pest management of brassica crops can be found at the Brassica Pest Collaborative website (https://ag.umass.edu/vegetable/resources/brassica-pest-collaborative). This project recently conducted several online workshops on managing insect pests of brassicas, including imported cabbageworm, cross-striped cabbageworm, cabbage maggot, flee beetle. All the webinars should be posted on the above website after April 12.  


Figure 1. Striped Cucumber Beetle feeding on a watermelon.

Striped cucumber beetle can be a significant pest in watermelon production systems. These pests can cause feeding damage to roots, stems, leaves, and flowers of plants as well as the watermelon fruit itself (Figure 1). In large enough densities, this damage can lead to economic loss. The economic threshold for striped cucumber beetles in watermelon has been set at 5 beetles per plant, since they are not susceptible to bacterial wilt. When densities of the beetles reach this level, growers should treat their fields with an insecticide to avoid yield loss. To make good decisions, pest densities should be determined with scouting. To investigate the pressure of striped cucumber beetles on commercial watermelon fields in Indiana we worked with 16 growers during the summers of 2017-18. Fields ranged in size from less than half an acre to 100 acres. The growers used a variety of management strategies and insect scouting[Read More…]


Insecticides are often needed to control pests in vegetable crops, but in crops that require pollinators we often worry about the impact those insecticides may have on those pollinators (Figure 1). In the summer of 2018, a team of researchers at Purdue University explored the effects of insecticide applications on watermelon yield across Indiana, considering their impacts on both pests and pollinators. Using 5 of the Purdue Agricultural Centers (PACs), pairs of ½ acre watermelons plots were planted, each in the middle of a 15-acre corn field (10 total plots) (Figure 2). The two watermelon plots at each site were assigned either to a conventional or an integrated pest management (IPM) system. The corn surrounding the conventionally managed watermelons had a neonicotinoid seed treatment, the watermelons were given a neonicotinoid soil drench at transplant, and 4-5 pyrethroid sprays were applied throughout the summer regardless of pest pressure. The IPM system[Read More…]


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…]


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