Greenhouse whitefly （GHWF）, Trialeurodes vaporariorum （Westwood） is a very important pest of greenhouse plants, but its resistance to pesticides has rendered it difficult to control by chemical methods in recent y...Greenhouse whitefly （GHWF）, Trialeurodes vaporariorum （Westwood） is a very important pest of greenhouse plants, but its resistance to pesticides has rendered it difficult to control by chemical methods in recent years. Sterile insect technique （SIT） is a biological control method which has been used in Area Wide Integrated Pest Management （AWIPM）. This study conducted the possibility of sterilising GHWF adults by gamma radiations emitted from cobalt 60. Longevity of the adults, and the amount of egg laying and sterilisation of eggs were determined under the influence of 50, 60, 70, 80, 90 Gy doses under controlled conditions （65 ± 5% RH, 25 ± 2 ℃, L/D = 16/8）. Normal insects were considered as control （0 dose）. The best combination for mating of normal and sterile adults （normal male × normal female as control, normal male and irradiated female, irradiated male × normal female, and irradiated male × irradiated female） was studied using a factorial design （n = 4）. Results showed that the best irradiating doses were 70 and 80 Gy for females and males respectively. Longevity of irradiated males and females was not significantly different from that of non-irradiated specimens. The best mating model was irradiated males and females.展开更多
The repellent activities, including host deterrence and anti-oviposion, of pongam oil against the adults of the common greenhouse whitefly Trialeurodes vaporariorum Westwood in greenhouses were tested. Chrysanthemum p...The repellent activities, including host deterrence and anti-oviposion, of pongam oil against the adults of the common greenhouse whitefly Trialeurodes vaporariorum Westwood in greenhouses were tested. Chrysanthemum plants treated with different concentrations （0.5%-2.0%） of water-suspended pongam oil showed relatively long-lasting host deterrent and anti-oviposition effects on the adults of greenhouse whitefly. Although the repellent effect declined in time and concentration, strong effects on the reduction of oviposition were found, which lasts, dependent on concentration at least 12 days after application.展开更多
The greenhouse whitefly, Trialeurodes vaporariorum (Westwood), is a major pest of tomato, Solanum lycopersicum L. Management in both the field and greenhouse is often based on foliar applications of insecticides. A la...The greenhouse whitefly, Trialeurodes vaporariorum (Westwood), is a major pest of tomato, Solanum lycopersicum L. Management in both the field and greenhouse is often based on foliar applications of insecticides. A lack of control along with resistance development requires development of alternatives to currently available insecticides. Pyrifluquinazon is a recently developed insecticide by Nichino/Nihon Nohyaku Co., Japan and is marketed in the US by Nichino America. The insecticide inhibits feeding by aphids, thrips, mealybugs and scale insects resulting in death. Because limited information exists on pyrifluquinazon effectiveness against whiteflies, tests were initiated to establish its toxicity against the greenhouse whitefly on greenhouse produced tomato. Data reported herein indicate that pyrifluquinazon was highly effective against adult greenhouse whiteflies. When adults were transferred to tomato shortly after the application had dried, mortality counts taken after 48 h produced LC50 and LC95 values of 0.2469 and 2.4826 μg·g-1, respectively. Although few adults were observed on tomato foliage 24 h post-exposure, little mortality was observed until the 48 h observation. When adult whiteflies were placed on tomato 3 d after pyrifluquinazon application, the LC50 value was 0.3343 μg·g-1 which did not significantly differ from the 0 h LC50 value. A significant increase in LC50 value was observed when adults were placed on tomato 5 d after pyrifluquinazon application. In a greenhouse efficacy trial, both the recommended pyrifluquinazon rate (46.8 g active ingredient [AI] ha-1) and a reduced rate (11.7 g·AI·ha-1) significantly reduced numbers of whitefly adults when compared to the non-treated control for 10 days. The 46.8 g·AI·ha-1 rate was as effective as the insecticide standard, imidacloprid. Pyrifluquinazon applied to tomato foliage in the greenhouse offers a useful alternative to currently available insecticides for control of greenhouse whitefly. Further, its unique mode of action may represent a new tool in management of insecticide resistance.展开更多
The greenhouse whitefly, Trialeurodes vaporariorum （Westwood）, is an important pest of strawberries in California, USA. The adults and nymphs feed on phloem sap of leaves to remove the photo-assimilates. The objecti...The greenhouse whitefly, Trialeurodes vaporariorum （Westwood）, is an important pest of strawberries in California, USA. The adults and nymphs feed on phloem sap of leaves to remove the photo-assimilates. The objective of this study is to test the impact of whitefly management with insecticides on strawberry fruit quality. Applications of imidacloprid, thiamethoxam, buprofezin and pyriproxyfen decreased the mean adult whitefly numbers by 2.80-, 2.17-, 1.69- and 1.39-fold, respectively, compared to the untreated control, Similarly, the mean numbers of first and second instar whiteflies were reduced 4.36-, 2.20-, 1.90- and 2.02-fold, respectively, while the mean numbers of third and fourth instars were reduced 5.48-, 2.28-, 2.71- and 1.43-fold, respectively, in plants treated with imidacloprid, thiamethoxam, buprofezin and pyriproxyfen. The mean soluble solids content in imidacloprid, thiamethoxam, buprofezin and pyriproxyfen treatments was 1.04-, 1.06-, 1.03- and 1.04-fold greater, respectively, than that in the control. The whitefly reduction enhanced the mean fruit titratable acidity by 4%-6%. Mean glucose levels in imidacloprid and thiamethoxam treatments were significantly higher than in other treatments. However, the whitefly management did not affect the mean fructose levels, lmidacloprid, thiamethoxam and pyriproxyfen treatments boosted the ascorbic acid levels by up to 4%. The impact of whitefly management on strawberry fruit nutrition and antioxidant capacity is discussed.展开更多
The poinsettia thrips Echinothrips americanus Morgan is a relatively new pest that has spread rapidly worldwide and causes serious damage in both vegetable and ornamental plants.In this study,we investigated if and ho...The poinsettia thrips Echinothrips americanus Morgan is a relatively new pest that has spread rapidly worldwide and causes serious damage in both vegetable and ornamental plants.In this study,we investigated if and how effective this pest can be controlled in gerbera by the omnivorous predator Macrolophus pygmaeus(Rambur).Because herbivores on plants can interact through a shared predator,we also investigated how poinsettia thrips control is affected by the presence of the greenhouse whitefly Trialeurodes vaporariorum(Westwood),a pest that commonly coexists with E.americanus in gerbera.In laboratory studies,we found that the predator M.pygmaeus fed on both pests when offered together.Olfactometer tests showed a clear preference of the predators for plants infested by whiteflies but not by thrips.In a greenhouse experiment,densities of both pests on single gerbera plants were reduced to very low levels by the predator,either with both pests present together or alone.Hence,predator‐mediated effects between whiteflies and thrips played only a minor role.The plant feeding of the shared predator probably reduced the dependence of predator survival and reproduction on the densities of the two pests,thereby weakening potential predator‐mediated effects.Thus,M.pygmaeus is a good candidate for biological control of both pests in gerbera.However,further research is needed to investigate pest control at larger scales,when the pests can occur on different plants.展开更多
文摘Greenhouse whitefly （GHWF）, Trialeurodes vaporariorum （Westwood） is a very important pest of greenhouse plants, but its resistance to pesticides has rendered it difficult to control by chemical methods in recent years. Sterile insect technique （SIT） is a biological control method which has been used in Area Wide Integrated Pest Management （AWIPM）. This study conducted the possibility of sterilising GHWF adults by gamma radiations emitted from cobalt 60. Longevity of the adults, and the amount of egg laying and sterilisation of eggs were determined under the influence of 50, 60, 70, 80, 90 Gy doses under controlled conditions （65 ± 5% RH, 25 ± 2 ℃, L/D = 16/8）. Normal insects were considered as control （0 dose）. The best combination for mating of normal and sterile adults （normal male × normal female as control, normal male and irradiated female, irradiated male × normal female, and irradiated male × irradiated female） was studied using a factorial design （n = 4）. Results showed that the best irradiating doses were 70 and 80 Gy for females and males respectively. Longevity of irradiated males and females was not significantly different from that of non-irradiated specimens. The best mating model was irradiated males and females.
文摘The repellent activities, including host deterrence and anti-oviposion, of pongam oil against the adults of the common greenhouse whitefly Trialeurodes vaporariorum Westwood in greenhouses were tested. Chrysanthemum plants treated with different concentrations （0.5%-2.0%） of water-suspended pongam oil showed relatively long-lasting host deterrent and anti-oviposition effects on the adults of greenhouse whitefly. Although the repellent effect declined in time and concentration, strong effects on the reduction of oviposition were found, which lasts, dependent on concentration at least 12 days after application.
文摘The greenhouse whitefly, Trialeurodes vaporariorum (Westwood), is a major pest of tomato, Solanum lycopersicum L. Management in both the field and greenhouse is often based on foliar applications of insecticides. A lack of control along with resistance development requires development of alternatives to currently available insecticides. Pyrifluquinazon is a recently developed insecticide by Nichino/Nihon Nohyaku Co., Japan and is marketed in the US by Nichino America. The insecticide inhibits feeding by aphids, thrips, mealybugs and scale insects resulting in death. Because limited information exists on pyrifluquinazon effectiveness against whiteflies, tests were initiated to establish its toxicity against the greenhouse whitefly on greenhouse produced tomato. Data reported herein indicate that pyrifluquinazon was highly effective against adult greenhouse whiteflies. When adults were transferred to tomato shortly after the application had dried, mortality counts taken after 48 h produced LC50 and LC95 values of 0.2469 and 2.4826 μg·g-1, respectively. Although few adults were observed on tomato foliage 24 h post-exposure, little mortality was observed until the 48 h observation. When adult whiteflies were placed on tomato 3 d after pyrifluquinazon application, the LC50 value was 0.3343 μg·g-1 which did not significantly differ from the 0 h LC50 value. A significant increase in LC50 value was observed when adults were placed on tomato 5 d after pyrifluquinazon application. In a greenhouse efficacy trial, both the recommended pyrifluquinazon rate (46.8 g active ingredient [AI] ha-1) and a reduced rate (11.7 g·AI·ha-1) significantly reduced numbers of whitefly adults when compared to the non-treated control for 10 days. The 46.8 g·AI·ha-1 rate was as effective as the insecticide standard, imidacloprid. Pyrifluquinazon applied to tomato foliage in the greenhouse offers a useful alternative to currently available insecticides for control of greenhouse whitefly. Further, its unique mode of action may represent a new tool in management of insecticide resistance.
文摘The greenhouse whitefly, Trialeurodes vaporariorum （Westwood）, is an important pest of strawberries in California, USA. The adults and nymphs feed on phloem sap of leaves to remove the photo-assimilates. The objective of this study is to test the impact of whitefly management with insecticides on strawberry fruit quality. Applications of imidacloprid, thiamethoxam, buprofezin and pyriproxyfen decreased the mean adult whitefly numbers by 2.80-, 2.17-, 1.69- and 1.39-fold, respectively, compared to the untreated control, Similarly, the mean numbers of first and second instar whiteflies were reduced 4.36-, 2.20-, 1.90- and 2.02-fold, respectively, while the mean numbers of third and fourth instars were reduced 5.48-, 2.28-, 2.71- and 1.43-fold, respectively, in plants treated with imidacloprid, thiamethoxam, buprofezin and pyriproxyfen. The mean soluble solids content in imidacloprid, thiamethoxam, buprofezin and pyriproxyfen treatments was 1.04-, 1.06-, 1.03- and 1.04-fold greater, respectively, than that in the control. The whitefly reduction enhanced the mean fruit titratable acidity by 4%-6%. Mean glucose levels in imidacloprid and thiamethoxam treatments were significantly higher than in other treatments. However, the whitefly management did not affect the mean fructose levels, lmidacloprid, thiamethoxam and pyriproxyfen treatments boosted the ascorbic acid levels by up to 4%. The impact of whitefly management on strawberry fruit nutrition and antioxidant capacity is discussed.
基金This study was funded by the Dutch Product Board for Horticulture.Part of this work was supported by COST Action FA 1105:Towards a sustainable and productive EU organic greenhouse horticulture.
文摘The poinsettia thrips Echinothrips americanus Morgan is a relatively new pest that has spread rapidly worldwide and causes serious damage in both vegetable and ornamental plants.In this study,we investigated if and how effective this pest can be controlled in gerbera by the omnivorous predator Macrolophus pygmaeus(Rambur).Because herbivores on plants can interact through a shared predator,we also investigated how poinsettia thrips control is affected by the presence of the greenhouse whitefly Trialeurodes vaporariorum(Westwood),a pest that commonly coexists with E.americanus in gerbera.In laboratory studies,we found that the predator M.pygmaeus fed on both pests when offered together.Olfactometer tests showed a clear preference of the predators for plants infested by whiteflies but not by thrips.In a greenhouse experiment,densities of both pests on single gerbera plants were reduced to very low levels by the predator,either with both pests present together or alone.Hence,predator‐mediated effects between whiteflies and thrips played only a minor role.The plant feeding of the shared predator probably reduced the dependence of predator survival and reproduction on the densities of the two pests,thereby weakening potential predator‐mediated effects.Thus,M.pygmaeus is a good candidate for biological control of both pests in gerbera.However,further research is needed to investigate pest control at larger scales,when the pests can occur on different plants.
