Does Host Plant Chemistry Influence Feeding and Ovipositional Behavior of Fruitborer in Tomato?

摘要

The tomato fruitborer (TFB), Helicoverpa armigera Hub., is one of the most difficult pests to control with insecticides. Development of cultivars that are resistant to this insect has become an important strategy in management. Resistant/tolerant accessions of tomato (Lyco-persicon esculentum Mill.) to TFB have been identified based on feeding and ovipositional behavior of TFB. The moths laid more eggs on accessions LE 4 (52 eggs/plant), LE 104 (73) and LE 281 (57) than on LE 355 (11). Biochemical assays indicated that the acylsugar contents in leaves of tomato accessions varied from 38 to 266 nmol/cm2. High acylsugar content was negatively associated with number of eggs laid/ plant (r = -0.94). Content of alpha-tomatine in fruit varied from 0.57 to3.51 mg-g~(-1) of fresh tissue. The alpha-tomatine concentration was weakly, and negatively, associated with percent fruit damage by TFB (r = -0.39). The fruit pigments lycopene and carotene influenced the feeding of TFB as there were differences in feeding of TFB on ripened and unripened fruits. The lycopene (r = -0.93) and carotene (r = -0.58) contents were negatively associated with feeding by TFB. Acylsugars, alpha-tomatine and various pigments in tomato accessions may be, in part, responsible forpossible resistance to TFB.