Laura Ingwell

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.

38 articles by this author

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Aphids have been a particularly challenging pest to get under control this spring. They quickly colonized the strawberries we had growing all winter in our high tunnels, and took off as the weather sporadically warmed up (Figure 1). In my first attempt to knock them back I introduced 2,000 lacewing larvae (22-Apr), too little too late. Four days after release I did not recover a single one. They were either hiding or did not survive. However, last week I found very large larvae (Figure 2), just one or two here and there. In the meantime, I decided to try out a few of the OMRI approved options. I will admit that at the time of the first application, the populations were high, and it explicitly states on the label for some of these products (BotaniGard® and Grandevo®), to begin applications at the onset of pest detection. That was not the[Read More…]

Info about the culprit insect: Cutworms are the larval (caterpillar) stage of moths in the family Noctuidae, which typically fly at night. Although the adult moths are not damaging, the voracious larvae can be! The caterpillars typically hide during the day and emerge at night, curling around young, tender plants to feed. How many kinds of cutworms are there? There are several species of cutworms, but you are most likely to encounter one of four species of cutworm in Indiana: either the dingy, variegated, or clay backed cutworms, which overwinter as partially grown larvae, or the black cutworm, which does not overwinter in the Midwest, but migrates back each year. The black and clay backed cutworms are leaf feeders and plant (stem) cutters, while the dingy and variegated cutworms are mainly leaf feeders that rarely cut plants at or below the ground level. What crops do cutworms attack? Cutworms are[Read More…]

Fig. 2 Maggot in young onion transplant with a penny referenced for size. Photo by John Obermeyer.

Each and every spring we get reports of poor seed emergence, seedling and transplant damage in early planted crops of all sorts. Most recently in untreated sweet corn, home gardens and transplanted onions. Lucky for us, we got to dive right into this pest and see them in action, but not so lucky for the growers who weren’t expecting it! While we don’t have a lot to offer in terms of a rescue for these crops affected this year, we hope to help you plan for this in the future and understand what the threat looks like for the remainder of the season. There are two different species to blame: the Onion Maggot (Delia antiqua) and the Seed Corn Maggot (Delia platura). There is a third species that attacks brassica crops referred to as the Cabbage Root Fly (Delia radicum). All three are nearly identical to the naked eye but[Read More…]

Figure 2: Heavy aphid infestation of the buds of strawberries in a high tunnel.

This winter-spring has been my first excursion into growing strawberries in a high tunnel. It didn’t take much for our own Wenjing Guan to convince me to plant some; who doesn’t love to eat fresh strawberries? We planted them back in October and I just peeked at them every couple of weeks throughout the winter, looking for hungry herbivores wanting to share the impending treats. There were spider mites at first (Figure 1) and we made a few releases of the predatory mites Phytoseiulus persimilis and sachets containing Amblyseius (Neoseiulus) Californians. Figure 1. Two-spotted spider mites on strawberry leaves (above) and under a microscope camera (below). This spring, when the weather started warming up and the extra cover was lifted inside the tunnels we found less mites, almost none at all at this point, but an explosion of aphids (Figure 2) and an increasing presence of whiteflies (Figure 3). The[Read More…]

As you prepare to fill your high tunnels and greenhouses or even field plots, take a close peek at the weeds in your area. There can be some sneaky pests that have overwintered on the plant material in and around your farm. In high tunnels in particular, I have recently found overwintering populations of two spotted spider mites and a variety of aphid species. Before you put those tender little transplants into these environments, be sure to get rid of the straggling weeds and insects. Remove the plant material, move it away from your growing space, and allow some down time before you move the new crops in. Aphids and mites can not survive without living plant material. They will not overwinter in the soil, they need to be feeding on active growing plant material. Happy growing season!

While not a new technology, I thought it timely to talk about the use of yellow sticky cards as a monitoring tool. These cards will not manage insect pests in your crops, but can be a very valuable monitoring tool in high tunnels and greenhouses. Many of the insect pests that migrate into our crops move on wind currents (aphids and mites for example) or the people working in these spaces. Strategically placing sticky cards around the borders of a planting, where they can intercept wind currents, or along high traffic areas, is a great strategy for monitoring early signs of infestations. Considerations: The industry has come to the consensus that yellow sticky cards are the best tool. There is no need to invest in cards with other colors. Some cards also contain pheromones, an added chemical to attract a particular pest. For general monitoring this is not necessary. For[Read More…]

As the days grow shorter and those of you who adventure into winter production begin to prepare your seed starts, keep an eye out for unwanted invaders. Pests such as thrips, mites and aphids may be on the move as our field production dwindles, and nothing is tastier than a tiny new plant! In order to increase the success of winter production, be sure that you are starting with clean plants before you tuck them away under those cozy row covers! Controlling weeds, which can serve as alternative hosts to the aphid pests, will lessen problems of re-infestation. Scout with diligence for aphids, they can be one of the most damaging and hard to control pests during the winter months in high tunnels. The first step to managing aphids is to develop a scouting plan. Aphids reproduce clonally and develop quickly leading to very large population build-up in a short[Read More…]

The sweet corn variety plots at Pinney Purdue provide a good chance to observe sweet corn insects. In late July I observed two caterpillars that surprised me. The first was European Corn Borer (ECB), in the tassel where they are often found (Figures 1 & 2). It was a surprise because I have seen many fewer of these in the sweet corn plots in recent years. I understand from the entomologists that it is due to the widespread use of Bt field corn that has resulted in much lower populations of ECB. The week of Aug. 19 I observed an ECB egg mass on a flag leaf and a young larva on the ear (Figures 3 & 4). The second late July observation was a corn earworm (CEW)–the insect itself is not surprising, but it was in the tassel! (Figures 5-8). I have previously only seen them in ears. The[Read More…]

Recently we have received reports of swarms of hover flies (aka syrphid flies) around Indiana and wanted to take the opportunity to tell you a bit about this curious insect (Figure 1). Adult hover flies can sometimes be mistaken for bees or wasps, because they look a lot like them! Some people refer to hover flies as “sweat flies” or “sweat bees,” but these insects are actually quite different from bees. Hover flies belong to the Order Diptera, or the true flies. The most abundant group at this time of year belong to the genus Toxomerus, which feed on pollen (Figure 2) rather than other soft-bodied insects, like aphids. Hover flies are typically lighter in color, have a characteristic abdomen-bobbing behavior, and cannot sting at all – in fact, they are harmless. Sweat bees, on the other hand, are typically dark or metallic in color, smaller than common bees and[Read More…]

Winter squash – butternut, acorn, and kabocha – in our downy mildew sentinel plot at Pinney Purdue were showing some wilted and stunted plants by late July (Figure 1). They are easily pulled up, the stem breaking off at ground level, revealing a brown stringy decayed-looking stem base (Figure 2). Sometimes there is a little whitish or maybe pinkish mold on the stem. I cut open a kabocha squash to look for squash vine borer larva and found sap beetles that seemed to be feeding inside the stem, but no vine borer (Figure 3). The sap beetles were clearly taking advantage of an opportunity, but not the cause of the wilt. Perhaps a borer had already come and gone. I used scotch tape to pick up some of the mold and put it on a slide to look at under the microscope. At 100X and 400X I saw among the[Read More…]