SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/484138
Field Science 12 SportsTurf | April 2015 www.sportsturfonline.com Field Science have tested this product for more than 3 years and it regu- larly provides 70-80% control of Japanese beetle and masked chafer grubs when applied in July and early August. There are two more beetle-active strains of Bt known, but neither has reached the turfgrass markets. Spinosyns are the chemicals that are excreted by a soil- dwelling microbe, Saccharopolyspora spinosa. Spinosyns are available in Conserve from Dow. This molecule is very active on caterpillars and recent data indicates that it is relatively active on the annual bluegrass weevil. While there are some certified organic versions of spinosyns, none of those labels currently have turfgrass listed. Chromobacterium subtsugae strain PRAA4-1T was recently registered by Marrone for turfgrass use under the trade name of Grandevo. I believe that this product needs more test- ing, but we have seen significant population reductions of chinch bugs and sod webworms following applications of this product. Studies on billbug and white grub larvae have been inconsistent, suggesting that the formulation may need to be modified to get this product to the target insects. The chinch bug control is especially interesting as these are sucking insects that wouldn't normally pick up a microbial pesticide unless the chemical has some contact toxicity attributes! Azadirachtin (primarily as Azatrol) has also provided good chinch bug and sod webworm control. Two applications, about 14 days apart are often needed for chinch bug control but a single application can eliminate caterpillars. Using resistant tUrfgrasses In many areas of extreme restrictions, reseeding, precise fertiliz- ing and mowing are the only options for dealing with sport field maladies! In the insect world, the use of endophyte enhanced turfgrass species and cultivars is an option to be considered! There have been major improvements in the heat tolerance and cold hardiness of turf-type tall fescues and perennial ryegrasses, the main grasses with endophytes that are useful on sport fields. Turf-type tall fescues are especially useful as they also have more fibrous and deep roots. In field studies, tall fescues are more tolerant of white grub populations without showing signs of attack. The endophytes of both tall fescue and peren- nial ryegrasses produce natural toxins that kill off billbugs, sod webworms, armyworms and chinch bugs. In athletic fields, you don't need a 100% stand of endo- phytic grasses to eliminate most of the pests. Field studies have shown that about 40% of the stand has to have stems that contain the endophytes. So, slit seeding or interseeding over a couple of seasons can usually reach this level of protection. On the other hand, if you are going to completely renovate a field going with a solid stand of one of these grasses is fine! One caution about endophytic turfgrasses. The endophytic fungus is passed on in the seed, but the tiny endophyte starts can die off if the seed is stored too long or subjected to high temperatures. Because of this, you should contact your see provider and explain that you need recent harvest seed of cul- tivars that are high in endophytes. This request may cost a bit more, but the long-term benefits will pay for this increase. In summary, there ARE some biological and biobased turf- grass insect management tools. If these are to be used, you will need to do some studying and careful reading of the labels to achieve the desired results. In most cases, the younger the target pest, the more efficacious these alternative products will be. It's also a good idea to thoroughly read the information packets that the suppliers have prepared. These informational pieces (and websites) often have some tips on how to maximize efficacy. And, finally, work toward developing sport fields that use the most resistant and tolerant species and cultivars of grasses. ■ ST Dr. David Shetlar is Professor of Urban Landscape Entomology, The Ohio State University, Department of Entomology, Ohio Agriculture and Development Center and Ohio State Extension. LEFT: A masked chafer larvae that has been killed by the green fungus of insects. TOP RIGHT: A billbug adult killed by Beauveria, the white fungus that attacks insects. BOTTOM RIGHT: This masked chafer larva was killed by Heterorhabditis nematodes that normally turn their victims a reddish color.