The Effect of Salicylic Acid (SA) on The Biology of The Two Spotted Spider Mites. Tetranychus urticae (Koch ) (Acari: Tetranychidae) on The Egg Plant Khalid A.

Abstract

Induced resistance has been studied ni the two spotted spider mites Tetranychus urticae(KOCH) . It is on the treatment of the plant of eggplant with salycilic acid (henceforth SA) of thefollowing types of concentration:100 mg/L, 200 mg/L, 300 mg/L and 400 mg/L. taking Larva , nymphs,and adults of eggplant mites separately. It has been found out that these treatments have got their effect onthe life of the pest under investigation. The lowest percentage on hatching at the concentration of 400mg/L reads 21.67%, 32%, and 33.67% within 24, 48, and 72 hours respectively. On the other hand, thehighest percentages at the concentration of 100 mg/L are 45%, 59% , and 71.67% respectively. Thedifferences between the treatments and durations have been found to be statistically significant at the0.01 degree of freedom. The comparison process has shown a great percentage of hatching that differencereads 98.33% after 72 hours. The highest percentage of the death of larva has been 58.33% at theconcentration of 400mg/L whereas the death percentage of larva at the concentration of 100mg/L hasbeen reported to be 25% after 72 hours. There has been statistically significant differences between thetreatments in question. In relation to the effect of SA on nymphals is so evident that the death percentagereads 27.67% during the first nymphal phase at the concentration of 100mg/L after 72 hours. Anyhow,this percentage increases at the concentration of 400mg/L and after 72 hours to be 52.33% and 57.67%during the first and second phases respectively. And at 0.01 degree of freedom there are statisticallysignificant differences. Moreover the accumulation of SA inside the body of the nympth plays a great rolein the physiological changes. As far as the adults are concerned, the percentage of death was 33.33% atthe concentration of 100mg/L after 72 hours. Finally the percentage of death of the adults is 54.33% atthe concentration of 400mg/L after 72 hours and statistically significant differences have been noticed aswell.