The Relationship between population fluctuations of Helopeltis theivora Waterhouse, availability of Cocoa Pods and Rainfall Pattern

Investigation on factors affecting the population fluctuations of Helopeltis theivora in relation to food supply and rainfall in the field was conducted. Results showed that population fluctuations seem to be dictated by rainfall and numbers of available pods as shown by positive correlations between them. The results also showed a significant yield decrease with increased mind populations. The numbers of cherelles and pods on a tree determine it attractiveness, since significantly more cherelles and pods were found on infested trees than on uninfested trees

Biotype and insecticide resistance status of Bemisia tabaci populations from Peninsular Malaysia

Bemisia tabaci, a resistance-prone insect pest, is a cryptic species complex with important invasive biotypes such as B and Q. The biotype and resistance statuses of this pest in Malaysia remain unclear. This study assessed the biotype and resistance status of a number of contemporary populations of B. tabaci based on the mtCO1 marker and the dose-response method, respectively. The Pahang (PHG) population was labelled as the Q biotype, while the remainder of the populations belonged to the Asia 1 biotype. A very low level of resistance for profenofos, cypermethrin, and imidacloprid was detected for all populations [resistance factor (RF) 100). All populations showed a very low level of resistance against pymetrozine except Q-type PHG population, which exhibited a very high level of resistance. For most insecticides, the highest level of resistance was detected in the PHG population. The implications of these findings for better management of this noxious pest are discussed

Hexokinase, Malate Dehydrogenase, Fluorescent Esterase and Malic Enzyme Polymorphisms in the Cocoa Pod Borer, Conopomorpha cramerella (Snellen)

Cocoa pod borers collected in the field from Tawau, Sabah and from Sua Betong, Negeri Sembilan and rambutan fruit borers collected from Puchong and the campus of Universiti Pertanian Malaysia (UPM) in Serdang, Selangor, Malaysia were analysed by polyacrylamide gel electrophoresis. Hexokinase was found to be polymorphic in the UPM population, malate dehydrogenase in the Tawau, Sua Betong and UPM populations and fluorescent esterase and malic enzyme were polymorphic in all four populations

Toxicity, antifeedant, egg hatchability and adult emergence effect of Piper nigrum L. and Jatropha curcas L. extracts against rice moth, Corcyra cephalonica (Stainton)

Petroleum ether extract of black pepper, Piper nigrum and physic nut, Jatropha curcaswere shown to have insecticidal efficacies against rice moth, Corcyra cephalonica(Stainton). The C. cephalonica 3rd instar larvae were shown to have similarities susceptibility to petroleum ether extract of Piper nigrum and J. curcas with LC50 values of 12.52 and 13.22 µL/ml, respectively. In a bioassay using no-choice tests, the parameters used to evaluate antifeedant activity were relative growth rate (RGR), relative consumption rate (RCR), efficiency on conversion of ingested food (ECI) and grain protection or feeding deterrence indices (FDI). Both extracts showed high bioactivity at all doses against C. cephalonica larvae and antifeedant action was increased with increasing plant extract concentrations. The petroleum ether extract of P. nigrum and J. curcas showed strong inhibition on egg hatchabilities and adult emergence of C. cephalonica at the lowest concentration. Based on the results of this study, petroleum ether extracts of P. nigrum andJ. curcas could be used in IPM program for rice moth

Molluscicidal and feeding deterrent activity of crude plant extracts on Pomacea maculate Perry

This study was focused on molluscicidal effect and feeding deterrent activity of saponin from five different plant materials; Andrographis paniculata, Entada spiralis, Ficus deltoidea, Furcraea selloa and Ipomoea batatas. Crude plant extracts were prepared from plant powders using methanol. The crude extracts were then tested on Pomacea maculata using five different concentrations (5, 10, 15, 20 and 25 ppm, respectively) against niclosamide (control). After 72 h of exposure, the highest percentage of mortality of 80% was achieved from 15 ppm of F. selloa. Two analyses were conducted to observe the feeding deterrent activity and after 24 h, both analyses demonstrated the feeding deterrent activity in both crude extracts (F. selloa and E. spiralis) similar in niclosamide

Damage potential of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) on cocoa beans: effect of initial adult population density and post infestation storage time

The effect of different initial adult population densities of Tribolium castaneum (Herbst) at several post infestation storage times on the final adult population density, the percentage of damaged beans, the percentage of weight loss, and the weight of insect feeding residues on cocoa beans was investigated in laboratory experiments. Both factors interactively had highly significant (P < 0.01) effects on variables assessed. The highest mean final adult population density of 129.7 ± 4.6 was recorded in samples infested with the highest initial adult population density and stored for 150 d, while the least mean adult population density of 10.8 ± 0.54 was recorded on samples infested with the lowest initial adult population density in samples stored for 30 d. The highest percentage damaged cocoa beans 51.0 ± 1.21% was recorded in samples infested with the highest initial adult population density, while the least mean percentage damaged beans of 16.9 ± 1.26% was also recorded on samples infested with the lowest initial adult population density. Similar trends of means were recorded for all the remaining variables. Correlation between factors was significant and positive. Multiple and simple linear regressions analyses were also significant (P < 0.01) and all equations fitted the regression models and perfectly described the relationship between the independent and the dependent variables. Our results show that T. castaneum can impact negatively on both the quantity and quality of stored cocoa within just 30 days of infestation, with the impact increasing with increasing population density and post infestation storage time

Response of Diaphorina citri Kuwayama (Hemiptera:Psyllidae) to volatile emmitted from leaves of two Rutaceous plants.

Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important worldwide pest of citrus, because of its ability to vector the three phloem-restricted bacteria in the genus Candidatus Liberibacter, that cause citrus greening or huanglungbing. Studies were conducted to examine the effects of flush growth stage and volatile compounds emitted by two rutaceae plants on oviposition and feeding site selection of D. citri. Three methods including choice, no choice and Y tube olfactometer assays were conducted using plants with only newly expanded leaves (4-6 days old), plants with all leaves completely hardened (14-21 days old) and plants without leaves (14-21 days old). The results showed that significant number of adult D. citri were attracted to plants with newly expanded leaves for oviposition and feeding in both choice and no choice assay, and when the two plants were assayed together in Y tube, significant number of the adults select Y tube arm with Citrus suhuiensis leaves and similarly in choice assay more adults select C. suhuiensis for oviposition and feeding than Murraya paniculata. The results gave an insight into response of D. citri to different plant forms and volatiles emitted by the plant which is useful in monitoring and management of the pest

Effectiveness of various botanical traps against apple snail, Pomacea maculata (Gastropoda: Ampullariidae) in a rice field

The adverse effects of molluscicides applied for the control of the invasive apple snails, Pomacea spp., have led to the search for eco-based cultural, mechanical and biological control techniques. Therefore, a field study on the relative effectiveness of locally available and cost effective plant-based traps against Pomacea spp. was conducted. Results showed jackfruit skin (9.03 ± 0.60/m2 and 6.03 ± 0.60/m2) and damaged pomelo (9.00 ± 0.61/m2 and 5.78 ± 0.74/m2) were relatively more effective than tapioca leaves, water spinach leaves and old newspaper. Snails also displayed preference for fresh materials as compared to rotten materials. Thus, incorporating these findings in rice fields during early susceptible growth will ease the collection and destruction of snails

Determination of larval instar of Bactrocera papayae (Diptera : Tephritidae) on guava, Psidium guajava, Linn. based on morphometric characters

Morphometric characters such as length and width of the Bactrocera papayae larvae could be used to determine the larval instars at their immature stage. Observation in this study indicated that B. papayae underwent three larval instars. The duration for the first instar, second and third instar was 4,4 and 7 days respectively. There was a significant difference in the length and width within larval instars of B. papayae. After hatching, the length of the larvae was 1.04 mm and the longest could reach up to 8.32 mm while the width starts from 0.18 mm and could reach up to 2.08 mm before completing all instars during the immature stage. Means length of the larvae were 1.27 ± 0.03, 4.33 ± 0.05 and 7.84 ± 0.07 mm whilst means width were 0.23 ± 0.01, 1.04 ± 0.01 and 1.85 ± 0.03 mm for the first instar, second instar and third instar respectively. Moulting process of the larvae occurred twice between day-4 and day-5 and also between day- 8 and day-9