Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 28, 2001
Publication Date: N/A
The primary pest of sugarbeets, the root maggot (SBRM), has largely been managed with at-plant treatments with varying success. The regulatory review mandated by the Food Quality Protection Act may have implications for continued registration of insecticides for sugarbeets, emphasizing a need for alternative control measures. A SBRM fungal pathogen, Syngliocladium tetanopsis, has been patented and is being developed as a biological control agent. Over thirty isolates from the Red River Valley of ND and MN have been purified and cultured. Bioassays with third instar SBRM co-cultivated with S. tetanopsis conidiospores for 7 days at 23oC resulted in 85-93% mortality. The primary penetration of the SBRM cuticle occurrd within 12 h after contact with conidia. To enhance spore viability and the time to sporulation in culture, oat based carbon and nitrogen sources (i.e., oatmeal, oat bran, commercial cereals) were modified with vegetable oil and cholesterol. Supplemental nitrogen sources (i.e., casei hydrolysate, tryptone, peptone) have been found to enhance conidial germination but were detrimental to spore production and had morphogenetic effects on culture development. Dipteran larvae of the house fly (Muscao domestica) and fruit fly (Drosophila melanogaster) were not susceptible to infection by the evaluated isolates of S. tetanopsis. Bioassays with three coleopteran, one lepidopteran and one neuropteran species also showed a lack of pathogenicity, suggesting a very narrow host range of this fungus. Experiments are underway to evaluate other dipteran species.