Laura Ingwell

Entomology
Area(s) of Interest: Vegetable Pest Management, Protected Agriculture, Controlled Environment Agriculture, Urban Agriculture
I work on insect pest management and pollination in horticultural crop production. I specialize in high tunnel production systems, examining biological control and conventional pest management strategies and the impacts of agricultural inputs on crop pollinators with an emphasis on managed bumble bees. I am interested in evaluating organic and conventional pest management with an emphasis on sustainable practices for food production.

32 articles by this author

Article List

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…]


Figure 2: Some of the tomato plants in this photo have been stunted as a result of infection by tomato spotted wilt virus.

This disease was recently observed in a tomato greenhouse. This article will review tomato spotted wilt virus symptoms, biology and management. Tomato spotted wilt virus (TSWV) and the closely related Impatiens necrotic spot virus (INSV) are usually observed in greenhouse or high tunnel situations. 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 a necrotic mottle caused by TSWV. Figure 2 shows tomato plants stunted as a result of infection by TSWV. Additional symptoms may be viewed here . Since the symptoms of these two viruses vary, plants with suspicious symptoms should be submitted to the Purdue Plant and Pest Diagnostic Laboratory for confirmation of virus symptoms. TSWV and INSV cannot spread without thrips. Thrips are small[Read More…]


Bacterial wilt is a serious pest of cucumbers and melons. This disease is caused by the bacterium, Erwinia tracheiphila. However, it is spread by the striped or spotted cucumber beetle. Most management schemes have concentrated on controlling the cucumber beetle in order to lessen the severity of bacterial wilt. Currently, management of bacterial wilt often takes the form of a soil applied systemic insecticide such as Admire Pro® at transplanting and follow up pyrethroid products applied foliarly about 3 weeks post transplanting. The pyrethroid applications are made when the 1 beetle per plant threshold is met. Every year, there is a melon variety trial at the Southwest Purdue Agriculture Center in Vincennes, IN. In 2018, the trial included several specialty melon varieties. We noticed more bacterial wilt than usual (Figure 1). Therefore, we decided to rate the varieties to see if there were any differences in susceptibility. Figure 2 shows[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…]


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…]


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


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…]