Preliminary results on insecticidal and repellent activity of ProAlexinTM on Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and citrus mealy bug, Planococcus citri (Risso)

Mediterranean fruit fly (or Med-fly) Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) (known as Mediterranean fruit fly or Med-Fly) and citrus mealybug, Planococcus citri (Risso) (Homoptera: Pseudococcidae), are plant pests capable of causing extensive damage to a wide range of fruit crops in many areas of the world.

ProAlexin^TM Nutrient Synergist is a mixture of citrus biomass and palm oil extracts, rich in flavonoids and ascorbic acid. These elements show synergistic effects, allowing the plant naturally to suppressing pathogenic attack and preserving the natural flavor of vegetables and fruits. Flavonoids and ascorbic acid are extremely powerful elicitors of phytoalexins, as well as they act in combination as stabilizers towards oxidisable substances present in fruit and vegetables. The scope of the present study was to determine any lethal or repellent negative effects of ProAlexin^TM products on the Mediterranean fruit fly, Ceratitis capitata, and the citrus mealy bug, Planococcus citri.

For the Med-fly, choice experiments were conducted in room conditions, in which ten citrus med fly adults were released in a screen-house (Bug-Dorm S.A.), containing sweet oranges treated with ProAlexin^TM and untreated, serving as controls. Every hour, presence of Med-fly adults on fruits was counted.

Also, in field experiments, four treatments with ProAlexin^TM products were being applied to single-tree plots of sweet orange in a completely randomized design. Trees used were ‘Valencia’ sweet orange which had not been treated with any other chemical compound for several months prior to use in experiments. Five treatments in total were conducted in 10 day intervals, beginning from October 9^th, in order to cover the period in which fruits are susceptible of Med-fly attack. Untreated trees were used as controls. In order to detect any attack of Med-fly on fruits, optical observations have been conducted from the beginning of the sprayings to ten days after the last one was applied.

For the citrus mealy bug, in laboratory conditions Viburnum tinus fully expanded leaves were placed in petri dishes containing dumped cotton. Five citrus mealybug of different nymphal instars taken from stock colonies were caged in each petri dish. Petri dishes were divided in groups of five and received five different treatments, plus a spray with water, serving as control. Mealy bugs were checked daily for survival.

Results will be presented and discussed.