Showing papers by "National Chung Hsing University published in 1982"
TL;DR: In this article, 15 insecticides were tested for their efficacy against one susceptible (S) and two field (Peng-hu and Ban-chau) strains of Plutella xylostella (L).
Abstract: Fifteen insecticides were tested for their efficacy against one susceptible (S) and two field (Peng-hu and Ban-chau) strains of Plutella xylostella (L.). The synthetic pyrethroids (permethrin, cypermethrin, decamethrin, and fenvalerate) had the highest inherent toxicity to the S strain, and the organophosphorus compounds were one to two orders less effective, except Tokuthion® (O-2,4-dichlorophenyl-O-ethyl, S-propylphosphorodithioate), which was almost as toxic as the four synthetic pyrethroids. DDT, cartap, and methomyl were intermediately toxic, whereas carbaryl and propoxur were the least effective. The Peng-hu strain was only slightly resistant, whereas high levels of resistance to all compounds tested were observed in the Ban-chau strain. Nevertheless, the four synthetic pyrethroids remained the most potent, followed by Tokuthion,® cartap, and dichlorvos, to this highly multiresistant population of the diamondback moth.
65 citations
TL;DR: To elucidate the potentiality of the wild progenitor to evolve the two types of Indica and Japonica when domesticated, the selfed progenies from an Indica × wild and a japonica ×Wild cross were examined with regard to three characters known to be useful for distinguishing between the two type.
Abstract: Studies of intermediate wild-cultivated plants suggested that the Indica-Japonica differentiation of cultivars of Oryza sativa L. has taken place with the domestication of wild plants. The wild progenitor, which is considered to be the Asian form of O. perennis
Moench, shows no trace of differentiation into two such types as the Indica and Japonica. To elucidate the potentiality of the wild progenitor to evolve the two types when domesticated, the selfed progenies from an Indica × wild and a japonica × wild cross were examined with regard to three characters known to be useful for distinguishing between the two types. The data showed that Japonica-like plants were derived from the Indica × wild cross and Indica-like plants from the Japonica × wild cross. The Indica-Japonica differentiation was considered to have resulted from selection of incipient domesticates having such potentiality under different climatic conditions; the dynamics was discussed.
55 citations
TL;DR: A malathion-resistant strain of Nilaparvata lugens (Stal) developed in the laboratory by continuous selection of a field strain for nine generations gained 1,183-fold resistance as compared with a susceptible strain.
Abstract: A malathion-resistant strain of Nilaparvata lugens (Stal) developed in the laboratory by continuous selection of a field strain for nine generations gained 1,183-fold resistance as compared with a susceptible strain. An MIPC-resistant strain selected similarly for 16 generations developed 41-fold resistance. Both were equally and significantly resistant to propoxur and permethrin while remaining susceptible to fenvalerate. Field strains from heavily treated areas showed similar patterns of resistance to these chemicals.
19 citations
TL;DR: Although pb synergized DDT by twofold against the susceptible strain, it produced very little effect in the resistant strain, raising the possibility of existence of a nonmetabolic mechanism of DDT resistance in the diamondback moth.
Abstract: Susceptible and multiple-resistant (resistance ratio for DDT = 200) strains of diamondback moth, Plutella xylostella (L.), were used to determine the effect of a microsomaloxidase inhibitor, piperonyl butoxide (pb) and a DDT-dehydrochlorinase inhibitor, DMC, on DDT toxicity. For both strains, DMC did not increase, but as a mailer of fact, decreased DDT toxicity somewhat. Although pb synergized DDT by twofold against the susceptible strain, it produced very little effect in the resistant strain. The absence of synergisym by pb and DMC raised the possibility of existence of a nonmetabolic mechanism of DDT resistance in the diamondback moth. This mechanism might also play an important role in diamondback moth resistance to synthetic pyrethroids and may be similar to previously described nonmetabolic mechanism for DDT-pyrethroid resistance in houseflies and mosquitoes.
10 citations
TL;DR: Higher MLVSS loading rates can be applied to a final clarifier without impairing its separation efficiency because of the excellent settleability of the Predenitrification activated sludge.
Abstract: A laboratory study has been conducted to obtained preliminary process information of a suspended growth Predenitrification (SGPDN)system. System performance was evaluated, in terms of chemical oxygen demand (COD) removal, NH(3)-N removal, system biomass yield and inventory, and effluent qualities, at different solids retention times (SRTs) and recycle ratios. Chemical oxygen demand removal in an SGPDN system occurs mainly in the anoxic reactor, which accounts for 94% of total COD removal. The overall COD removal rate is independent of recycle ratio (ranging from 2-5) used in this study; however, effluent COD increase with increasing recycle ratio. The observed anoxic and aerobic COD removal rates decrease with increasing SRT. The NH(3)-N removal in an SGPDN system is induced by two mechanisms: assimilatory NH(3)-N requirement for biomass production in the anoxic reactor and nitrification in the aerobic reactor. The observed anoxic NH(3)-N removal rate relates directly to the anoxic COD removal rate and agrees fairly well with the assimilatory NH(3)-N requirement theoretically predicted. The overall NH(3)-N removal rate is independent of SRTs and recycle ratios used in this study. Biomass yield in an SGPDN system occurs mainly in the anoxic reactor. However, uniform distribution of biomass throughout the entire system is obtained because of the high recycle rate used. The observed biomass yield (Y(O)) decreases with increasing STR. Tertiary treatment efficiency can be achieved in an SGPDN system. More than 90% reduction in feed COD., feed NH(3)-N, and NO(2) + NO(3)-N is obtained at all SRTs and recycle ratios used in this study. Higher MLVSS loading rates can be applied to a final clarifier without impairing its separation efficiency because of the excellent settleability of the Predenitrification activated sludge.
6 citations
TL;DR: The effect of partial defoliation and depodding on the C2H2 reduction, H2 evolution and respiratory activities of mungbean nodules were evaluated and the respiratory cost appeared to be dependent on both growth stages and organ removal treatments.
5 citations
TL;DR: Nephotettix cincticeps Uhler, a green rice leafhopper collected from 10 locations throughout Taiwan, was highly resistant to malathion, methyl parathions, and carbaryl, but remained susceptible to both permethrin and fenvalerate, which indicated that no cross resistance existed between organophosphorus or carbamate and synthetic pyrethroid insecticides.
Abstract: Nephotettix cincticeps Uhler, a green rice leafhopper collected from 10 locations throughout Taiwan, was highly resistant to malathion, methyl parathion, and carbaryl. However, it remained susceptible to both permethrin and fenvalerate, which indicated that no cross resistance existed between organophosphorus or carbamate and synthetic pyrethroid insecticides.
1 citations