Saturday, August 16, 2008

Turf - New Materials for Surface Feeders

Over the last few years several new products have become available for the control of surface feeding insect pests in turfgrass. Some of these new products are simply combinations of previously available active ingredients, others are new members of already available insecticide classes, and two actually belong to new insecticide classes.

Clothianidin (Arena) and thiamethoxam (Meridian) are two new neonicotinoids that, like imidacloprid (Merit), are primarily white grub products but can also be effective against billbugs by killing the younger larvae when feeding inside the grass stems. Both also claim chinch bugs on their label, although thiamethoxam with the caution that it only provides suppression. However, both would not exactly be my first choice for chinch bug control. Among the neonicotinoids, clothianidin has the best environmental profile as it is (based on EPA standards) ‘practically non-toxic’ to mammals, birds, and fish, and also has the lowest water solubility. Thiamethoxam is ‘slightly toxic’ to mammals and birds, ‘practically non-toxic’ to fish, but has a fairly high water solubility. Therefore, it has to be used carefully in situation where groundwater contamination potential exists. In comparison, imidacloprid is ‘moderately toxic’ to mammals, ‘practically non-toxic’ to birds and fish, and is only slightly more water soluble than clothianidin.

Two newer products are combinations of the pyrethroid bifenthrin and a neonicotinoid: Allectus (bifenthrin + imidacloprid) and Aloft (bifenthrin + clothianidin). These combination products simultaneously provide control of white grubs (through the neonicotinoid) and surface feeding insects (through bifenthrin). Both provide control of almost all the common turfgrass insect pests. However, along the same lines, they will also be very ‘effective’ against most non-target insect in turfgrass such as predators and parasites of turfgrass pests. Before applying these combinations, consider how likely both white grubs and surface insect pests are to occur in the same turfgrass area, let alone damage it. If a turfgrass area has the potential for problems with white grubs and surface feeders, make sure not to apply the combination more than 3–4 weeks before the surface feeders should be controlled to avoid the loss of bifenthrin activity. These combinations can be considered ‘moderately toxic’ to mammals and ‘practically non-toxic’ to birds. Because the bifenthrin component is ‘very highly toxic’ to fish but essentially not water soluble, these products have to be applied with care wherever there is a chance of surface water contamination.

Another recent addition to the turfgrass insecticides is the oxadiazine insecticide indoxacarb (Provaunt) which is highly effective against caterpillar pests (sod web-, cut-, armyworms) and annual bluegrass weevil larvae (Table 1). Indoxacarb also has a good environmental profile being ‘slightly toxic’ to mammals, ‘practically non-toxic’ to birds and fish, and essentially not soluble in water.

The anthranilic diamide insecticide chlorantraniliprole (Acelepryn) just received registration. It is not only highly effective against all the important white grub species, but also controls the caterpillars (sod web- , cut-, armyworms) and larvae of billbugs and annual bluegrass weevil. Against chinch bugs it only provides suppression. Ongoing research indicates that chlorantraniliprole will control caterpillars for 2-3 months, i.e., cover at least two generations. Chlorantraniliprole has an exceptional environmental profile being ‘practically non-toxic’ to mammals, birds, fish, and honey bees, and essentially not soluble in water.

Reprinted from "New Products for Surface Feeding Insect Pests in Turfgrass" by Albrecht M. Koppenhöfer, Ph.D., Turfgrass Entomology, Rutgers University in the July 24, 2008 edition of the Plant and Pest Advisory, Landscape, Nursery, and Turf Edition, Rutgers University.

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