Masters Thesis

Biological control of yellow nutsedge with Bactra verutana

Yellow nutsedge, Cyperus esculentus L., has been described as one of the world's worst weeds in cotton, orchards, vegetable crops, and vineyards (24, 26, 39). Yellow nutsedge, nutgrass and chufa are names commonly applied to this perennial noxious weed. As its name implies, nutsedge reproduces by nutlets, which botanically are tubers. It also reproduces by rhizomes and propagation by seed is another important method of reproduction (22). The use of a biological agent for control of yellow nutsedge was recently investigated by Poinar (26) and Keely (23). These investigations revealed that a moth, Bactra verutana Zeller var. chrysea Heinrich, was a possible biological control agent for yellow nutsedge. Bactra verutana is distributed throughout much of the United States. The California State Department of Agriculture reported that occurrence of this species is widespread in the state from San Diego to Butte Counties. The larval stage has been found in California as early as April 15 and as late as December 15, feeding on both species of nutsedge. Bactra verutana feeds predominantly on the vegetative portion of this plant, but effective control of the two nutsedge species has rarely been reported. The purpose of this study was to ascertain the usefulness of B. verutana as a biological control agent for yellow nutsedge.

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