7/22/2010 7:58:30 PM
Rice farmers in Louisiana who use seed treatments to manage insect pests in their fields may have a choice of seed treatments in 2010. Dermacor™ X-100 (DuPont Crop Protection), which has been available to farmers in Louisiana on a provisional basis (“Section 18” emergency exemption) the past two years, is expected to be available again in 2010, and Cruiser® (Syngenta), another insecticidal seed treatment, was recently approved for use in Louisiana under a full (“Section 3”) label. Although these two insecticidal seed treatments are similar in many respects, they also differ in key ways.
Understanding the similarities and differences between the two seed treatments is crucial to making the right choice of insecticides for each rice field. The key pest targeted by both Dermacor and Cruiser is the rice water weevil, the most important early-season insect pest of rice in Louisiana. Dermacor has been evaluated against the rice water weevil in multiple small-plot tests over several years at the LSU AgCenter Rice Research Station in Crowley. In addition, it has been used commercially in Louisiana the past two growing seasons. Dermacor provides excellent control of rice water
weevil larvae. In commercial fields, weevil populations were reduced by 90-95% compared to fields not treated for weevils. Cruiser has also been evaluated in multiple smallplot trials over many years at the Rice Station, and it too provides good control of rice water weevil larvae (although, in a side-by-side comparison of Dermacor and Cruiser conducted in 2009 at the Rice Research Station, control of weevil larvae given by Cruiser was not as good as control given by Dermacor).
Cruiser has not been evaluated on a commercial scale in Louisiana. In Arkansas, however, where Cruiser was available under a Section 18 exemption last year, Cruiser provided good control of weevils in commercial fields. Thus, there is every reason to believe that Cruiser will provide satisfactory control of weevils under most conditions in Louisiana.
Probably the most important difference between the two seed treatments is their activity against secondary pests. Because these two chemicals belong to different chemical classes (the active ingredient in Dermacor is a type of anthranilic diamide, whereas Cruiser is a neonicotinoid), they are effective against different pests. Cruiser will probably provide better control of grape colaspis (present in a few fields in southwest Louisiana last year) than will Dermacor. Cruiser also will provide good control of sucking insects such as aphids and chinch bugs. Dermacor, on the other hand, should provide excellent control of early-season Lepidopteran pests such as fall armyworms. Recent evidence from both Louisiana and Texas indicate that Dermacor may stay in the rice plant long enough to provide some protection against stem-boring insects. Evidence from Texas also indicates that Dermacor may help control the South American rice miner in rice. The spectrum of pests controlled by each of these seed treatments is probably the most important consideration in choosing between the two.
As a related consideration, Cruiser will be marketed in 2010 as part of a seed treatment package (CruiserMaxx® Rice), which includes fungicides that help control seedling diseases. The agronomic practices used with each of these seed treatments have similarities and differences. A similarity is that neither product can be used in water-seeded rice. They are for use in drill-seeded rice only. A difference is that the application rate of Cruiser will not change with rice seeding rate, whereas with Dermacor, the application rate is adjusted for seeding rate. This may make Cruiser easier to use, but it should be noted that the use of Cruiser at very low seeding rates (for example, seeding rates typically used for hybrid rice varieties) has not been tested by the LSU AgCenter. Pricing of these two products has not been formally announced. Because the rate of Cruiser applied to seeds is not adjusted for seeding rate, this product will probably be cheaper to use when low seeding rates are used.
The expected availability of two seed treatments for insect control in rice, along with other available products for insect control (Karate, Mustang Max, and the other pyrethroids), gives Louisiana farmers a wide range of options for managing their insect pests in drill-seeded rice. Unfortunately, there are not as many choices in water-seeded rice, and expanding the range of options for insect management in water-seeded rice is a continuing focus of entomology research.