94 articles tagged "Insect and Mite Management".

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…]

When houseplants and garden seedlings are kept too wet, roots can rot and the fungus that grows in the soil can feed fungus gnats. For houseplants, fungus gnats are usually just a nuisance. When growing seedlings or in a greenhouse adults can spread fungal diseases to flowers. Larvae can spread fungal diseases when they feed on roots. Where to fungus gnats come from?  Fungus gnats can get in the home when plants are brought in from outside, or when transplanting plants with infested potting soil. How do you manage fungus gnats? Avoid overwatering your plants. Plants need less water in cloudy days in winter and spring. As such, it is easy to overwater plants if you water by the calendar.   It is better to check you plants to see if they need water by touching the surface to see if it is dry. After you water, do not let plants[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…]

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…]

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