A van Nieuwenhoven - Academia.edu (original) (raw)
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Papers by A van Nieuwenhoven
Environmental Entomology, 1996
Tetrastichus giffardianus Silvestri is a gregarious endoparasitoid of tephritid fruit flies in Ha... more Tetrastichus giffardianus Silvestri is a gregarious endoparasitoid of tephritid fruit flies in Hawaii. Although widely established in Hawaii, it has been largely overlooked in field surveys. Our objectives were to develop an efficient rearing technique for T. giffardianus, and to determine basic bionomic and demographic parameters, necessary in future augmentative and/or classical biological control programs. Exposure of 5-and 6-d-old Ceratitis capitata (Weidemann) larvae to parasitoids at a 5:1 host:parasitoid ratio resulted in relatively high parasitism rates (>55%). Increasing exposure times to parasitoids for~8 h did not reduced emergence rates. T. giffardianus successfully developed in Bactrocera dorsalis (Hendel), B. latifrons (Hendel), B. cucltrbitae (CoquiIlet) and C. capitata. Parasitism was highest in B. dorsalis (37%) and lowest in B. cucurbitae (5%). The longevity of ovipositing females was 60% lower than females deprived of hosts. Each female parasitized 9.1 C. capitata larvae in her lifetime and 0.8 :!: 0.13 larvae were parasitized per day. At 26°C, gross and net reproductive rates were 57.3 and 42.6 progeny per female per day, respectively. Peak parasitism of hosts occurred in 2-d old females, followed by a 2nd peak in 6-to 8-d-old females. The significance of T. giffardianus to biological control of tephritids is discussed.
IX International Symposium on Postharvest Quality of Ornamental Plants, 2009
Reliable and extensive product information is increasingly important in today's trade. Many items... more Reliable and extensive product information is increasingly important in today's trade. Many items are visible or known at time of sale. Unfortunately, internal quality is not. The service 'Evaluated vase life' provides information regarding internal quality to both growers and traders. Traders can use this information to make quality conscious purchases and to inform their clients. Growers can use the results for promotion or to adapt procedures if necessary. Vase life tests indicate variations within season and between growers. Differences in Botrytis infection is one of the causes of this variation. Botrytis infection strongly reduces vase life but is often not visible at time of auction. The auction assists growers that have a relatively short vase life by identifying problems in postharvest handling and conditions. Thus, improvements can be implemented in order to improve quality. Confrontation with disappointing test results can help motivate growers to adapt pre or post harvest factors. Testing vase life of new cultivars provides information to breeders, growers and traders in order to help selecting suitable cultivars. The Dutch auction thus assists in several ways quality conscious breeders, growers and traders to improve post harvest quality and customer satisfaction.
Environmental Entomology, 1996
Tetrastichus giffardianus Silvestri is a gregarious endoparasitoid of tephritid fruit flies in Ha... more Tetrastichus giffardianus Silvestri is a gregarious endoparasitoid of tephritid fruit flies in Hawaii. Although widely established in Hawaii, it has been largely overlooked in field surveys. Our objectives were to develop an efficient rearing technique for T. giffardianus, and to determine basic bionomic and demographic parameters, necessary in future augmentative and/or classical biological control programs. Exposure of 5-and 6-d-old Ceratitis capitata (Weidemann) larvae to parasitoids at a 5:1 host:parasitoid ratio resulted in relatively high parasitism rates (>55%). Increasing exposure times to parasitoids for~8 h did not reduced emergence rates. T. giffardianus successfully developed in Bactrocera dorsalis (Hendel), B. latifrons (Hendel), B. cucltrbitae (CoquiIlet) and C. capitata. Parasitism was highest in B. dorsalis (37%) and lowest in B. cucurbitae (5%). The longevity of ovipositing females was 60% lower than females deprived of hosts. Each female parasitized 9.1 C. capitata larvae in her lifetime and 0.8 :!: 0.13 larvae were parasitized per day. At 26°C, gross and net reproductive rates were 57.3 and 42.6 progeny per female per day, respectively. Peak parasitism of hosts occurred in 2-d old females, followed by a 2nd peak in 6-to 8-d-old females. The significance of T. giffardianus to biological control of tephritids is discussed.
IX International Symposium on Postharvest Quality of Ornamental Plants, 2009
Reliable and extensive product information is increasingly important in today's trade. Many items... more Reliable and extensive product information is increasingly important in today's trade. Many items are visible or known at time of sale. Unfortunately, internal quality is not. The service 'Evaluated vase life' provides information regarding internal quality to both growers and traders. Traders can use this information to make quality conscious purchases and to inform their clients. Growers can use the results for promotion or to adapt procedures if necessary. Vase life tests indicate variations within season and between growers. Differences in Botrytis infection is one of the causes of this variation. Botrytis infection strongly reduces vase life but is often not visible at time of auction. The auction assists growers that have a relatively short vase life by identifying problems in postharvest handling and conditions. Thus, improvements can be implemented in order to improve quality. Confrontation with disappointing test results can help motivate growers to adapt pre or post harvest factors. Testing vase life of new cultivars provides information to breeders, growers and traders in order to help selecting suitable cultivars. The Dutch auction thus assists in several ways quality conscious breeders, growers and traders to improve post harvest quality and customer satisfaction.