If you are growing asparagus, then it is that time of year to be aware of the only insect pest of asparagus; the common asparagus beetle. Adult beetles are only 1/4 inch long. Adults emerge from the soil in early spring and fly to new asparagus shoots where they mate and feed. Females lay up to 30 eggs on the end of spear tips as they emerge from the soil.
Common asparagus beetles overwinter underneath plant debris, loose bark, or hollow stems of old asparagus plants. The life cycle can be completed in eight-weeks. There are two generations in Kansas. The adults and larvae feed on asparagus spears and can defoliate ferns if populations are extensive. Larvae consume leaves and tender buds near the tips, which leaves scars that eventually turn brown. Damage caused by larvae interferes with the plant’s ability to photosynthesize (manufacture food); thus, depleting food reserves for next year’s crop.
To help protect your asparagus patch from beetles: applying insecticides; handpick eggs, adults, and larvae and place into a container with soapy water; and/or remove any plant debris after the growing season to eliminate overwintering sites for adults. Insecticides should be applied as soon as common asparagus beetles are present, and again in late summer through early fall to kill adults before they overwinter. Thorough coverage of all plant parts is important in suppressing populations.
Fall webworm feeds on almost all fruit, shade, and ornamental trees except conifers. This insect is present more often on trees that are not surrounded by other trees. The larvae begin by constructing small webs near the ends of branches. The insect will gradually increase the size of the web as the need for food increases.
Mature caterpillars are yellowish with black and brown markings, and have many tufts of long hair. As larvae mature, they crawl down the tree and spend the winter as pupa in the leaf litter under the tree.
High populations of fall webworm can completely defoliate host plants but do not kill them. However, on pecan trees, nut production and quality can be reduced if webworms are not controlled. On ornamental plants, control is optional.
Pruning and destroying the infested portions of branches is a common control practice while webs are still small. A stick or pole with a nail inserted crosswise can be used to snag individual webs. Twisting the pole after insertion will cause the web to wrap around the pole where it can be removed and destroyed. Instead of a nail inserted crosswise, some people use a toilet brush attached to the end of a pole. Insecticides can also be used for control but a commercial quality, high-pressure sprayer is needed to penetrate the webs. Numerous products can be used for control including spinosad (Conserve; Fertilome Borer, Bagworm, Leafminer and Tent Caterpillar Spray; Captain Jack’s Dead Bug Brew), cyfluthrin (Tempo, Bayer Vegetable & Garden Insect Spray) and permethrin (numerous trade names). We normally consider fall webworm damage to be purely aesthetic, and control is not needed to protect the health of the tree.
Squash bugs are the grey, shield-shaped bugs that feed on squash and pumpkin plants. If you have had problems with these insects in the past, you know that they are almost impossible to control when mature. This is because the squash bugs have a hard body that an insecticide has difficulty penetrating. Thus, spraying when the insects are small is important. We are now seeing the nymphs of the first generation. These nymphs will eventually become adults, which will lay eggs that will become the second generation. The second generation is often huge and devastating. Therefore, it is important to control as many squash bugs now as possible.
Because squash bugs feed by sucking juice from the plant, only insecticides that directly contact the insect will work. General use insecticides such as permethrin (Bug-B-Gon Multi-Purpose Garden Dust, Green Thumb Multipurpose Garden and Pet Dust, Bug-No-More Yard and Garden Insect Spray, Eight Vegetable, Fruit and Flower Concentrate, Garden, Pet and Livestock Insect Control, Lawn & Garden Insect Killer), malathion, and methoxychlor provide control if a direct application is made to young, soft-bodied squash bugs. This means that you MUST spray or dust the underside of the leaves because this is where the insects live.
Now is the time to start controlling bagworms. We often don’t think about control measures until it’s too late and the insects are already done feeding and in their bags. Controlling them before that stage is critical.
Have you ever been in your garden and found a mysterious insect, you weren’t sure what it was or how to control it? This program is for you! Our guest speaker will be State Extension leader for Entomology Dr. Raymond Cloyd. Dr. Cloyd will be talking about the top insects you might see this growing season. Join us Thursday, May 10th at 7:00pm, in the commercial building on the Cloud County Fairgrounds in Concordia, Kansas. This event is brought to you by K-State Research and Extension Horticulture Agents Cassie Homan from Post Rock District and Kelsey Hatesohl from River Valley District. Whether you have been gardening for years or are just getting started this program is open to all at no cost! Participants are asked to RSVP by May 7th to the Post Rock Extension Office at 785-738-3597 or by emailing Kelsey Hatesohl at email@example.com.