The Effects of Bacillus thuringiensis var. kurstaki on the First, Second and Third Larval Instars of Pistachio White Leaf Moth Ocneria terebinthina (Lep.: Lymanteridae)

In this research the susceptibility of the first three larval instars of Ocneria terebinthina (Lep.:Lymanteridae) to Bacillus thuringiensis var. kurstaki was investigated. The eggs of the insect werecollected from orchards where located around Rafsanjan. Different larval instars groups wereseparated by measuring the head capsule width and then used in all bioassays. In bioassays, LC50values of Bt on the first, second and third instars larval groups were determined. The data wasanalyzed by log-probit transformation using the MSTATC software. LC50 values for each group oflarvae were estimated by using treated pistachio offshoot. The LC50 values of Bt on the first, secondand third instars of larvae were 276.91, 1494.53 and 2817.34 ppm, respectively. The first larval instarwas the most susceptible to Bt. According to collected data in this research and the selective nature ofBt, we can conclude that this microbial compound can be used for reasonable control ofO. terebinthina.

The Effects of Bacillus thuringiensis var. kurstaki on the First, Second and Third Larval Instars of Pistachio White Leaf Moth Ocneria terebinthina (Lep.: Lymanteridae) Keywords:

Bacillus thuringiensis var. kurstaki , Ocneria terebinthina , LC50 , Pistachio , Biologicalcontrol