larvae, respectively, the highest success was recorded with 30 host larvae, but the differences were not significant. However, for the parasitoid densities, parasitism rate and female: male sex ratio were highest using a 3:3 male to female sex ratio as compared to 2:4 and 4:2 male to female sex ratios. The results show promise for efficiently mass rearing A. opuntiarum for use as a biological control agent of the cactus moth. Robert G. Shatters, Jr., Kasie Sturgeon and Erica Warwick - USDA-ARS, U.S. Horticultural Research Laboratory, 2001 South Rock Road, Fort Pierce, FL 34945; Robert.shatters@ars.usda.gov; 772-519-2689 Antimicrobial peptide that blocks ‘Candidatus’ Liberibacter asiaticus acquisition by Diaphorina citri (Asian citrus psyllid) in citrus leaves - ‘Candidatus’ Liberibacter asiaticus is a phloem-limited bacterium in citrus that causes citrus Huanglongbing (HLB or citrus greening disease). This bacterium is transmitted by Diaphorina citri (Asian citrus psyllid, ACP). There is no known cure for this disease and since its discovery in Florida in 2005, it has reduced commercial citrus production by greater than 70%. This bacterium cannot be cultured outside of citrus or the psyllid, thus, limiting research on development of new control strategies. We have developed a screening bioassay to test effectiveness of various antimicrobial compounds using a detached leaf assay. With this assay we have identified several compounds that can move into the phloem of detached leaves and kill up to 90% of CLas. Using a modification of this assay, we have also shown that psyllid acquisition of CLas feeding on leaves that have been treated with one specific antimicrobial peptide was greatly inhibited. In fact, we have been unable to detect CLas in the salivary glands of these psyllids and have yet to observe successful transmission to healthy citrus leaves. We are now evaluating various topical application strategies that can be used to deliver this peptide to plants in commercial groves.
larvae, respectively, the highest success was recorded with 30 host larvae, but the differences were not significant. However, for the parasitoid densities, parasitism rate and female: male sex ratio were highest using a 3:3 male to female sex ratio as compared to 2:4 and 4:2 male to female sex ratios. The results show promise for efficiently mass rearing A. opuntiarum for use as a biological control agent of the cactus moth. Robert G. Shatters, Jr., Kasie Sturgeon and Erica Warwick - USDA-ARS, U.S. Horticultural Research Laboratory, 2001 South Rock Road, Fort Pierce, FL 34945; Robert.shatters@ars.usda.gov; 772-519-2689 Antimicrobial peptide that blocks ‘Candidatus’ Liberibacter asiaticus acquisition by Diaphorina citri (Asian citrus psyllid) in citrus leaves - ‘Candidatus’ Liberibacter asiaticus is a phloem-limited bacterium in citrus that causes citrus Huanglongbing (HLB or citrus greening disease). This bacterium is transmitted by Diaphorina citri (Asian citrus psyllid, ACP). There is no known cure for this disease and since its discovery in Florida in 2005, it has reduced commercial citrus production by greater than 70%. This bacterium cannot be cultured outside of citrus or the psyllid, thus, limiting research on development of new control strategies. We have developed a screening bioassay to test effectiveness of various antimicrobial compounds using a detached leaf assay. With this assay we have identified several compounds that can move into the phloem of detached leaves and kill up to 90% of CLas. Using a modification of this assay, we have also shown that psyllid acquisition of CLas feeding on leaves that have been treated with one specific antimicrobial peptide was greatly inhibited. In fact, we have been unable to detect CLas in the salivary glands of these psyllids and have yet to observe successful transmission to healthy citrus leaves. We are now evaluating various topical application strategies that can be used to deliver this peptide to plants in commercial groves.