Laura Ingwell

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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…]


Entomologists are looking for the lettuce aphid, Nasonovia ribis-nigri. If you are growing lettuce, or other leafy greens, including under protected agriculture structures, please keep your eyes out for aphids. We will be using these insects in research examining pest management strategies in hydroponic vegetable production systems. We are aiming to develop low-input IPM strategies, compatible with organic production, to effectively manage aphid pests. Contact Dr. Laura Ingwell at (765) 494-6167 or lingwell@purdue.edu. Live specimens are needed, we will verify the identification of the species.


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…]


One can hardly glance at the news recently without noticing an item about the health of bees and other pollinators. We can all agree on the importance pollinators play in the health of our planet and the critical role honey bees and bumble bees play in agriculture. There is no doubt that populations of honey bees in particular have been in decline over the last several years. The multiple reasons for the decline are not as clear. This article will address the role that fungicides may play in bee health. There are many possible reasons for the decline of bee populations. Pesticides have been implicated in bee declines. Most experts would agree pesticides may play a role in bee population declines. The type of pesticide that is most often implicated in bee declines are the insecticides. This makes sense: bees are insects. There is less known about the role that[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…]


Entomologists are looking for growers willing to participate in research examining the detection and distribution of striped cucumber beetles. We would like to visit your fields on multiple occasions this year to count the number of cucumber beetles we encounter in your crop. If you grow slicing cucumbers in the field, and are interested in helping to improve our sampling recommendations for this pest, please contact Dr. Laura Ingwell at (765) 494-6167 or lingwell@purdue.edu


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 2: A tomato with tomato spotted wilt virus has necrotic ring spots.

While many virus diseases affect pepper and tomato plants, in the Midwest, the most common virus diseases of these two crops are tomato spotted wilt virus (TSWV) and Impatiens necrotic spot virus (INSV). These diseases are usually observed in greenhouse or high tunnel situations. The two viruses, TSWV and INSV are closely related. In fact, at one time, they were both considered TSWV. Therefore, the symptoms, biology and management of these two diseases are similar. This article discusses the symptoms, biology and management of these two diseases. Both TSWV and INSV affect many hosts, including vegetables and flowering ornamentals. Symptoms vary according to host, stage of plant affected and environmental conditions. Both diseases can cause stunting, yellowing, necrotic rings, leaf mottle and more. Figure 1 shows a tomato leaf with necrotic rings caused by TSWV. Figure 2 shows a pepper transplant with ring spots caused by INSV. Additional symptoms may[Read More…]