BY BALAKRISHNA RAO, PH.D.

Newly seeded lawns worms, I found that there are at least 14 over lawns in a zig-zag pattern at dusk In early spring, we seed lawns, then species associated with turfgrass in Vir- time. At this time, the females, who can have the problem of using pre-emer- ginia. This includes trisecta, Para- produce 200 in a lifetime, drop eggs gent herbicides to manage annual pediasia teterrella, Parapediasia decorella, on lawns. After about six days, eggs hatch grassy weeds. What are our choices? , , into tiny caterpillars. Can we use Drive herbicide on these ruricolella, Microcrambus ele- During the day, the caterpillars hide in newly seeded lawns? gans, Urola nivalis, , silken cocoons in thatch. At night, they — OHIO Pediasia luteolella, Pediasia caliginosella, come out and feed at the base of tillers. Agriphila vulgivagella, These chewing leave their excre- Depending upon the situation, you may be and Crambus perlellus. Only a few of ment and small patches of dead grass that able to use some herbicides such as Tuper- these, such as P. teterrella, N. elegans and appear to be scalped. The latter may re- san or Drive. P. trisecta, are found mostly during spring semble green pellets, which later turn Siduron (Tupersan) can be used on and summer. brown as they age. These, along with silken newly seeded turfgrass any time without a P. teterrella has two generations per cocoons and scalping-type feeding, are problem. year. Adults are seen during the second helpful in diagnosing sod webworm prob- Quinclorac (Drive) can be used when week of June and the first week of August. lems. the newly seeded turfgrass has germinated Larvae are found during the middle of July The larval stages may last for 50 days. and been mowed about three times. Re- and early September. They overwinter as fully grown caterpillars, ports indicate that Drive can be safely ap- M. elegans has two generations per then become pupae in the thatch. Pupae plied on perennial or tall fescue lawns year. Adults are seen during the third week become adults in about seven days during any time. On Kentucky bluegrass, the of June and the end of August. Larvae are spring and summer. treatment should be delayed for about 28 seen during July and October. Sod webworm caterpillars chew at the to 30 days after the seeds germinate. Avoid Trisecta has two to three generations. base of tillers and generally don't kill the treating fine fescue lawns with Drive herbi- Adult are found during the second turf. Therefore, if the infestation is light cide. week of June and the end of July. The lar- with the onset of cool and moist weather, Reports indicate that Drive herbicide vae are found during the second week of turf should recover as long as the crown is will perform well when the crabgrass is at July and the end of August. not dead for some other reason. If the the two- to three-leaf stage. Once the crab- Sod webworm activity periods vary in problem is severe, applications of insecti- grass begins to tiller, the efficacy of Drive different parts of Virginia. Consider moni- cides such as Dursban, Diazinon, Sevin, will be reduced. Therefore, use Drive be- toring them using black light traps to de- Talstar, Scimitar, DeltaGard, Conserve, M- fore tillering. termine their activity periods in a specific Pede or Tempo should help manage the area. Even though their activity period is problem. slightly different, their life cycle is similar. Read and follow Sod webworms For example, P. teterrella adults begin to label specifications We have found different kinds of sod appear around the first week of May. They for best results. webworms in lawns. Are there many are active during dusk, flying a short dis- kinds? If so, what are they and how are tance and folding their wings when at rest. they managed? They mate two to three days after emerg- — VIRGINIA ing, and eggs are laid in about two weeks. Generally, the ideal time to apply treat- In reviewing some literature on sod web- ments would be when you see adults flying

Manager of Research and Technical Development for the Davey Tree Expert Co., Kent, Ohio SEND YOUR QUESTIONS TO: "Ask the Expert" Landscape Management; 7500 Old Oak Blvd.; Cleveland, OH 44130, or email: [email protected]. Please allow two to three months for an answer to appear.