New Sugarcanes Sour Pest's "Sweet tooth"

Sugarcane growers stand to benefit from 12 new sugarcane germplasm strains that withstand a tiny, tunneling terror called the sugarcane borer, Diatrae saccharalis.

Borer larvae tunnel deep into the cane plant's stalk to feed and continue their transformation into adult moths. Inside the stalk, they're relatively safe from most predators, save the relentless fire ant. Cane growers race against time to spray their crop with insecticide before the borer reaches the plant's interior. But spraying becomes costly and poses an environmental risk.

The resistant sugarcanes should offer relief on both fronts. Several, for example, impede borer penetration with tough, outer rinds. Others produce natural chemicals that retard the pest's growth. The resistant strains, called clones, stem from more than 10 years of cross-breeding, development and field evaluation by scientists at Louisiana State University and the Agricultural Research Service. ARS is the chief scientific agency of the U.S. Department of Agriculture.

According to Bill White, an ARS entomologist, the borer is the most serious insect pest of sugarcane in Florida and Louisiana, where 35 percent of the nation's $1.5 billion crop is grown.

A grower's battle against the borer begins the moment it hatches from eggs laid on the plant's leaves. That's when insecticides and natural enemies like parasitic wasps are most effective in keeping its numbers to a minimum. A resistant cane crop would further ease the need for such chemical controls by buying beneficial insects more time, and blocking the borer's avenue of escape into stalks.

Of the 12 sugarcane clones developed, US93-15 proved the most resistant. When deliberately exposed to borer larvae in field studies, the clone's stalk suffered 85 percent less joint damage than other commercial check varieties.

Scientific contact: Bill White, USDA-ARS Sugarcane Research Unit, Houma, La., (504) 8725042, fax (504) 868-8369, [email protected].