Pustaka Ilmiah Universitas Padjadjaran

Abstrak

Mechanism And Effectiveness Of Safflower Oil Against Female Queensland Fruit Fly Bactrocera Tryoni

Queensland fruit fly , Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), infests many horticultural fruit crops in the eastern part of Australia. Farmers usually apply synthetic insecticides to control this pest. Little is known on the use of plant products especially vegetable oils for fruit fly control although they are considered to be safer than synthetic insecticides. In this study, safflower oil was investigated for its mechanism and effectiveness against female B. tryoni. In a laboratory test, saflower oil treatments (2.5 and 5.0 ml l-1) reduced the number of fly punctures on treated artificial fruits, no matter whether pre-punctures were present or absent. Saf?ower oil treatments also reduced the number of fly landings and eggs laid, but only when the treated arti?cial fruits were without pre-punctures. These results con?rmed that safflower oil is active against female B. tryoni mainly by preventing this fruit ?y from making oviposition punctures, not by discouraging them from depositing eggs or by repelling them. The slippery nature of safflower oil is considered to be responsible for a reduction in the susceptibility of artificial fruit to fruit fly punctures. Further investigation using fruit-bearing tomato plants (a no-choice test) in a glasshouse situation revealed that saflower oil application at concentrations of 10 and 15 ml l-1reduced the number of oviposition punctures but failed to reduce the number of eggs laid. To increase ef?cacy of saflower oil under field conditions, multiple tools may be needed to reduce fruit fly populations and oviposition behaviour, such as the addition of trap-crops, provision of arti?cial oviposition sites, or mixing the insecticides with the oil.