Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae) is one of the most serious pests on tomato. It is mainly controlled by chemical means, requiring some 25 sprays during the average growing season. The extensive and repeated use of insecticides has disrupted the natural balance between this pest and its natural enemies. In this study, Menochilus sexmaculatus F. was evaluated as a possible biological control agent of B. tabaci and its effect on gemini virus infestation. The study was conducted at the experimental station of the Indonesian Vegetables Research Institute (IVeGRI) in Lembang, West Java (1,250 m above sea level) from August to December 2008. The experimental plots consisted of 0.35 ha of tomato (± 100 m 2 per plot) and spatially separated with four rows of maize (a minimum of 1 m) interplot distance to prevent cross-contamination among plots. The experiment was arranged in completely randomized block design with eight treatments and four replications. M. sexmaculatus were released at 24 days after planting. The treatments were designed according dosages and schedules at three released populations (i.e. 10 predators per plot, 20 predators per plot, and 10 predators per plot at vegetative stage followed by 20 predators per plot at generative stage); two places of release (center and edge of the plot); and two schedules of release (weekly and biweekly). Efficacy of the predator was measured in terms of the density of B. tabaci, both before and after release of the predator and its effect on gemini virus infestation. The result indicated the potential use of M. sexmaculatus to control B. tabaci and its effect on gemini virus infestation on tomato. Reductions in B. tabaci populations and subsequent tomato yields were significant. B. tabaci population in plots receiving 10 predators showed 73.62% and 75.75% reductions by the end of experiment. The incidence and intensity of gemini virus were consistently and significantly lowest and tomato yield gain was observed when 10 predators were released at weekly intervals. It is suggested that release of M. sexmaculatus against B. tabaci on tomato may be offered as an alternative solution to increase implementation of biologically-based B. tabaci management.
Ten chili genotypes of germplasm collection had been evaluated under limited watering conditions. The objective of the research was to know the mechanism response of each treated genotype under limited watering conditions. The research was conducted from February to December 2017 at Indonesia Vegetables Research Institute, Lembang (1,250 m sal). A randomized complete design (RCD) was used as a research design with three replications. There were 20 treatments which combination between 10 chili genotypes with limited (interval per six days) or unlimited watering (per daily). The seedlings were planted in plastic pots with a mixture of media soil:sand = 1:2, then be applied treatments. The population number of each genotype per treatment was 15 plants/replication. The results showed that AN and 238 were a better tolerance level than other genotypes under-treated limited watering conditions by some mechanisms, i.e the smallest change in total chlorophyll, but increase in proline content, and reduction in leaf area index and stomata number. Moreover, genotype 238 also developed effectivity water absorption by root elongation at untreated stress conditions. Hence the results could determine a good strategy for each genotype to be improved as a new tolerant variety in water deficiency conditions.
Local cayenne can be used as a good genetic material for F-1 hybrid variety. The purpose of this research was to analyze and estimate general (GCA) and specific combining ability (SCA), heterosis, and heterobeltiosis value, then to evaluate and select F-1 progenies. The research was conducted from February to December 2019 at Indonesian Vegetables Research Institute, Lembang, (1,250 m sal). The genetic material consisted of six local cayenne lines i.e.: BNT, GNY, SGT, BGJ, HIU, MDN, 15 F-1 progenies, and STK as a commercial variety. The results showed that: (1) BGJ line had the highest GCA value on weight per one fruit (0.74), fruit length (0.77), fruit diameter (0.57), and fruit weight per plant (13.83), while the highest GCA value on fruit number per plant was MDN line (35.69); (2) F-1 SGT x HIU had the highest SCA value onr weight per one fruit (0.27), fruit length (0.56), and fruit weight per plant (69.90), while the highest SCA values fruit diameter (0.48) and fruit number per plant (129.29) were obtained by F1 HIU x MDN and F-1 BGJ x HIU respectively; (3) F-1 BNT x MDN, F-1 SGT x HIU, F-1 BGJ x MDN are recommended as advance hybrid lines.
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