Rate, placement and timing of aldicarb applications to control Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in oranges.

BACKGROUND

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a cosmopolitan insect pest of citrus and vectors the bacterium Candidatus Liberibacter asiaticus, a suspected causal organism of citrus greening or 'huanglongbing' disease. Aldicarb 150 g kg(-1) GR (Temik((R)) 15 G) was evaluated at three rates, two placements and three timings for ACP control in orange trees.

RESULTS

Application of aldicarb at 5.6, 2.8 and 1.4 kg AI ha(-1) in March 2006 reduced adults by 58-66%, 45-46% and 25-37% respectively compared with untreated controls in two separate trials. No difference was observed in placement (one versus two sides of the tree) or tree size (8 years old versus 12 years old). Application at 5.6 kg ha(-1) in January 2007 reduced adults by 86% and shoot infestation by 77% in spring, and was generally better than the November and especially February applications. Even more striking results were evident on adults caged on treated plants for 25 days in March. Spiders and ladybeetles were equally abundant in treated and untreated trees.

CONCLUSION

Aldicarb application at 5.6 kg ha(-1) to the bed side of mature citrus trees 2-3 months before spring growth can suppress ACP through spring without a direct effect on principal psyllid natural enemies.