Development of postharvest quarantine treatment against the western flower thrips Frankliniella occidentalis in pepper fruit

Abstract: The western flower thrips (WFT) Frankliniella occidentalis (Pergande) is a quarantine insect pest. In Israel, the WFT infestation is one of the limiting factors for sweet pepper fruit export, a very important part of the Israeli agricultural export. The pre-harvest treatments do not allow the zero WFT infestation, the strict importers requirement. Therefore, there is an urgent need to develop postharvest treatment in the pepper fruit, which will fit the quarantine requirements. Fumigation is a common quarantine treatment against insect pests in various agricultural commodities. However, the accepted fumigation treatment against the WFT in pepper fruits is absent. We evaluated some possibilities for effective WFT control in pepper fruits.Essential oils. In the laboratory experiments, some of the essential oils were tested. The pepper fruits were infested by adults/nymphs of the WFT and were treated in the glass chambers of 1.5 liters. The various concentrations and exposure period time were tested at least in three replications. The best results were obtained by the use of the mint essential oil at the concentration of 20 μl/l for 24 h exposure period.Ethyl formate. This compound was tested in the laboratory experiments similar to the essential oils. The total mortality of the WFT was obtained at the concentration of 20 μl/l for 24 h.Phosphine. The experiments were conducted in the fumigation room of 15-m3 volume. The pepper fruits were fumigated by Degesch-plates. Total WFT mortality was obtained at the rate of 2 g/m3 for 24 h. The concentration of phosphine was about 1000 ppm. All mentioned treatments might be used as a postharvest treatment against the WFT in the pepper fruits.