Economic thresholds of Thrips palmi (Thysanoptera: Thripidae) for eggplants in a greenhouse
Thrips palmi Karny has recently been implicated in damage to eggplant fruits. This thrips causes cosmetic scars on and deforms fruits, thus lowering their market value. To investigate the relationship between the density of thrips and the resulting damage, experimental plots with initial release densities of 0, 20, 40, 70, and 100 adults thrips per plot were established under greenhouse conditions. Thrips density (for flower sampling = x1; for sticky trap = x2) was monitored using flower sampling and blue sticky trap counts, and was found to be directly related to the proportion of damaged-fruits (y) and the reduction in fruit yield: significant relationships were found for the flower samples (y = 1.2261x1 − 0.6232, r2 = 0.8582) and for the trap catches (y = 11.667 ln(x2) − 9.5, r2 = 0.8896). The proportion of damaged fruits that could be tolerated from an economic perspective, based on the cost of controlling the thrips population chemically and the market value of the fruit, was 6.67–11.76 %; this translated into economic thresholds of 1.05–1.5 adults and/or larvae of T. palmi per flower or 4.91–10.17 adults T. palmi per four-day sticky card count.
Commodity risk assessment of Momordica charantia fruits from Mexico
Abstract The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as ‘High risk plants, plant products and other objects’. Momordica fruits originating from countries where Thrips palmi is known to occur qualify as high risk plants. This Scientific Opinion covers the introduction risk for T. palmi posed by fruits of Momordica charantia L. imported from Mexico, taking into account the available scientific information, including the technical information provided by the National Service of Health, Safety and Agrifood Quality (Senasica) of Mexico. The risk mitigation measures proposed in the technical dossier from Mexico were evaluated taking into account the possible limiting factors. An expert judgement is given on the likelihood of pest freedom taking into consideration the potential pest pressure in the field, the risk mitigation measures acting on the pest in the field and in the packinghouse, including uncertainties associated with the assessment. For T. palmi on M. charantia fruits from Mexico, an expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures acting on T. palmi, including any uncertainties. The Expert Knowledge Elicitation indicated, with 95% certainty that between 9,492 and 10,000 M. charantia fruits per 10,000 will be free from T. palmi.
Host Plants and Abundance of Thrips palmi Karny (Thysanoptera: Thripidae), an Important Pest of Vegetables in Southeast Asia.
host plants in Thailand, Malaysia nd the Philippines in 1987 and to cstimate the abundance of this thrips on difflrrent vege able crops in Thailand in 1987-1988 and in Malaysia in 1987. Z paimiwas found attacking anglcd loofah, bitter cucumber, cucumbcr, cggplant, goat peppcr, muskmelon, pumpkin, squash, watermelon, wax gourd, yard long bean, two species of I)haseotus and one unidentificd Cucurbitaccae. Of these crops, eggplant appeared to be most commonly infestcd with the thrips, The abundance of T paimi o]i cggplant in Thailand appcared to be influcnced by thc weather, pesticide applications and fruit bpe. Heavy rainfa11 during thc rainy season may be responsible for greatly reduccd populatioiis of 7I Paimi on eggplant. On the other hand, the high abundance ef 11 patmi obscrved in truck gardens growing a long fuiit eggplant in the dry season may have been induced by dcstruction ef natural enemy and competitoT populatiens frorn heavy insecticide usc. Kigy tuonis: 771iipspaimi, host plants, vcgetables, abundance, Southeast Asia