Opisthorchis viverrini is a carcinogenic parasite that can cause bile duct cancer called cholangiocarcinoma. A study of the immune response of this parasite in susceptible and non-susceptible hosts may provide a clue to develop vaccines and immunodiagnostic markers, which are currently not available. Here, we compared the antibody response in susceptible Golden Syrian hamsters and non-susceptible BALB/c mice infected by the liver fluke. In mice, the antibody was detected between 1 and 2 weeks post-infection, whereas it was positive between 2 and 4 weeks post-infection in hamsters. Immunolocalization revealed that the antibody from mice reacts strongly with the tegumental surface and gut epithelium of the worm, while hamster antibody showed a weak signal in the tegument and a comparable signal in the gut of the worm. Immunoblot of the tegumental proteins demonstrated that while hamster antibody showed a broad specificity, mice strongly reacted with a single protein band. Mass spectrometry revealed these immunogenic targets. Recombinant proteins of the reactive targets were produced in the bacterial expression system. The immunoblot of these recombinant proteins confirm the reactivity of their native form. In summary, there is a different antibody response against O. viverrini infection in susceptible and non-susceptible hosts. The non-susceptible host reacts quicker and stronger than the susceptible host.

Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating fungal disease of wheat (Triticum aestivum L.). The best economical technique for disease control is breeding for genetic resistance to stripe rust. To find resistance genes in landrace PI388222 from Pakistan, a segregating population was developed by a cross between PI388222 and susceptible Australian spring wheat line Avocet ‘S’. The F2:4 seeds were harvested and seeds were planted in the greenhouse of Washington State University Pullman, to grow F4:5 recombinant inbred lines (RIL). A variable set of seedling reactions were noted when a set of 136 F5 and parental lines were screened with four Puccinia striiformis f. sp. tritici races (PSTv-37, PSTv-40, PSTv-4 and PSTv-51). The great proportion of RILs showed resistant reaction displayed by the RILs was against PSTv-40, for which 85% of the RILs showed resistant reaction, while less resistance to the race PSTv-37 was detected against which the resistance was for only 49% of the RILs. The RIL population was further evaluated at two locations; Palouse Conservation Field Station (PCFS) and Mount Vernon (MV). In MV field, 76% of RILs displayed resistant reaction while 15% of RILs exhibited moderate reaction. About 53% of RILs exhibited resistant reaction to four P. tritici races that were used in glasshouse screening and they were also resistant in field environments at PCFS and MV. This study demonstrates that landrace comprises partial resistance in the range of resistant to moderately resistant lines.

Rate of seedling emergence, relative growth rate (RGR), and phenological development were compared in several accessions of rigid ryegrass belonging to three distinct resistance classes. The aryloxyphenoxypropionate resistant (AOPP-R) class had a faster and less variable seedling emergence than the sulfonylurea resistant (SU-R) and susceptible (S) classes. However, even the fastest of the AOPP-R accessions was within the range of the S and SU-R classes. No significant differences were detected among the resistant classes in seed dormancy, RGR, and the rate of phenological development. The rate of spike emergence, irrespective of the resistance class, was related to the latitude of the origin of the accessions, suggesting adaptation to the local climates since introduction. Due to considerable variation among weed populations for most biological attributes, the need to include several R and S accessions, in studies similar to the one reported here, is of vital importance. Because of the means and variances of the three resistance classes, at least four accessions from each resistance class would have been required to detect the observed differences between emergence rates of the AOPP-R and S classes with a confidence of 95%.

The uptake, distribution, and metabolism of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] by sugarcane (Saccharum officinarum L.) cultivars ‘PR980’ and ‘PR1048’ were determined 3 and 10 days after root treatment with 18.4 μM 14C-ring-labeled diuron. Uptake and distribution did not account for the differential tolerance of the two cultivars to diuron. Concentration of unmetabolized diuron was higher in the shoot and root of susceptible cultivar PR1048 than in tolerant cultivar PR980 at 3 and 10 days after treatment. The predominant metabolic pathway for diuron metabolism in both susceptible and tolerant sugarcane cultivars appeared to be the formation of mono-methyl diuron and its conjugation. The metabolic process was more rapid in PR980 than PR1048, apparently accounting for the tolerance of PR980.

In Australia Bt cotton has been planted since 1996, and has greatly improved the control of its key target Helicoverpa armigera (Hübner). There is no strong evidence that genetically modified cotton has been selected for significant physiological resistance to Bt toxin in field populations. There are many possible explanations for the lack of apparent selection that range from high compliance with the resistance management strategy for this technology to a lack of behavioral preference in key traits such as oviposition that could favor survival. To date most experiments that test oviposition of H. armigera on Bt cotton vs. conventional cotton have been done with susceptible moths. We determine the oviposition preference of a field isolated Bt resistant line of H. armigera and a susceptible counterpart when given a choice of non-Bt cotton and Bt-cotton with the same genetic background, and test whether there is any relationship between oviposition site selection (different plant structures) and the survival of the first instar larvae. Within cotton plants, our experiments consistently showed that both resistant and susceptible moths did not choose plants or plant parts that were less toxic in terms of Bt toxin on which to lay eggs. There was one exception in that susceptible moths were more likely to lay eggs on squares of Bt cotton plants than squares of non-Bt cotton. As expected, the mortality of susceptible H. armigera neonates was significantly higher on structures of Bt cotton plants than on those structures of conventional cotton, and survival was greater on flowers than on other structures of Bt cotton. This confirms opportunities for selection for resistance, and demonstrates no advantage in this respect to carrying resistance genes that might overcome the Bt toxins.

In this paper we develop some results presented by Gani (2004), deriving moments for random allocation processes. These moments correspond to the allocation processes reaching some domain boundary. Exact formulae for means, variances, and probability generating functions as well as some asymptotic formulae for moments of random allocation processes are obtained. A special choice of the asymptotics and of the domain allows us to reduce a complicated numerical procedure to a simple asymptotic one.

Genetic analyses were carried out to determine inheritance of resistance, heterotic effects and reciprocal effects for resistance to the spotted stem borer, Chilo partellus in three maize crosses. Resistance was found dominant over susceptibility. Highly significant heterosis was detected for percentage dead hearts. Both additive and nonadditive gene effects were important in the inheritance of resistance to C. partellus in all crosses. Additive gene effects were highly significant for all the three resistance parameters: leaf-feeding, dead hearts and stem tunnelling. However, a high magnitude of nonadditive (dominance and epistatic) gene effects were detected for dead hearts. No cytoplasmic effects were detected in reciprocal crosses between resistant and susceptible maize lines, suggesting that the resistance to C. partellus is conferred only by nuclear genes. Recurrent selection methods should be used to accumulate alleles for resistance. Resistant F1 hybrids could be developed between resistant and susceptible lines in reciprocal combinations.

This paper considers a carrier-borne epidemic in continuous time with m + 1 > 2 stages of infection. The carriers U(t) follow a pure death process, mixing homogeneously with susceptibles X0(t), and infectives Xi(t) in stages 1≦i≦m of infection. The infectives progress through consecutive stages of infection after each contact with the carriers. It is shown that under certain conditions {X0(t), X1(t), · ··, Xm(t) U(t); t≧0} is an (m + 2)-variate Markov chain, and the partial differential equation for its probability generating function derived. This can be solved after a transfomation of variables, and the probability of survivors at the end of the epidemic found.

DDT and BHC were used prior to 1954 as grain protectant but gradually malathion was adopted as prophylactic spray at 50 mg/m2. However, during the continuous usage, doses were enhanced up to 150 mg/m2 to meet the level of effective kill. Toxicity studies on different surfaces, seeds, moisture content level, different insects and stages and emergence of resistance were carried out with respect to malathion and several newer insecticides. DDVP was incorporated in spray schedule at 100 mg/m2. Toxicity data on 17 insecticides, three formulations, persistence on six surfaces and three seeds, tests on 13 insects have been utilized to evolve a strategy for future developments of a prophylactic insecticides. Demerits of switching to new insecticides without broad-based toxicity data have also been advocated. Insects, such as, larva of Trogoderma granarium Everts and adults of Tribolium castaneum (Hbst.), Rhizopertha dominica Fab., Callosobruchus maculatus Fab., Lasioderma serricorne Fab. and Sitophilus oryzae Linn, among beetles and Ephestia cautella (Wlk.) and Corcyra cephalonica Staint from moths were found least susceptible to most of the insecticides. Etrimfos and deltamethrin were adjudged superior for large scale use specially as wettable powder and adjudged suitable to sub-tropical conditions. The paper also provides information on currently used insecticides in India, methods of grain storage at rural and organized level and various constraints faced in the developing countries.

The relative resistance of rice varieties to Maliarpha separatella was studied during 1981 and 1982 long rain seasons. The observations covered the laying of egg masses, tiller infestation, incidence of “whiteheads” and, in some cases, the grain yield.

The results indicated that the varieties BG 34™8 and BG 90™2 received the highest egg masses per plot which apparently caused “whiteheads”. The remaining 10 varieties only indicated moderate response. The 1982 long rain season under no control and carbofuran 5G application regimes showed reduced tiller infestation only in BG 90™2 and Basmati 217. The five tested varieties did not show any marked difference in tiller infestation under the two regimes. Hence, BG 90™2 and Basmati 217 showed some susceptibility of M. separatella, while the rest of the varieties remained moderately resistant.

Moth population varied according to the growth stages of the rice crop in the field, with the peak occurring during the booting to maturation stages.

The behaviour of shootfly resistance is examined over the Fl, F2, F3 and advanced generations. The Fl is almost intermediate between two parents with an added heterotic advantage of a lower ‘dead-heart’ percentage. Resistance shows partial dominance under low to moderate shootfly infestation but this relationship may shift under heavy infestation conditions.

The resistance is polygenic in nature and governed by additive genes. In the absence of host immunity, gradual accumulation of favourable genes is possible by line breeding from R × I and I × I crosses by selecting 1 SD below the population mean. Selection for multiple characters limits the genetic advance for shootfly resistance—resulting in 0- 5% selection intensity and relatively less resistant but high yielding desirable progenies. Multilocation tests enable the selection of varieties stable for shootfly resistance.