THE BIOLOGY AND CONTROL OF SOME COMMON LEPIDOPTERAN PESTS OF VIRGINIA TOBACCO

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MD. JUSOH MAMAT and LIM GUAN SOON

SUMMARY

The biology of the three common lepidopteran pests of tobacco; Chloridia assulta, Spodoptera litura, and Psara submarginalis were studred. and found to have a life cycle of 16-29, 13-32, and 21-35 days respectively. Among these species, S. litura was noted to be most productive with a high net reproductive rate of 318.1 as compared to C. assulta and P. submarglnalis (38.0 and 49.0 respectively). The studies also showed that there was about 40-50% real mortalitv for all the three species under laboratory rearing conditions. Their survivorship curves were of the convex type where a higher mortality occurs towards the end of the life span. About 60% of the population apparently succumbed to old age while, 40% to egg, larval, and pupal mortality. Among the eight insecticides evaluated in the field on tobacco as foliar sprays/drench, it was found that not all the test chemicals were equally effective against the three lepidopteran species. In general, permethrin, metamidophos, decamethrin, and monocrotophos were more effective as compared to triazophos, Mega BT + Nu-Film-17, carbaryl, and fenvalerate all of which were significantly better than the untreated controls.

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THE ENERGY REQUIREMENTS FOR MAINTENANCE OF PEN-FED SHEEP IN MALAYSIA

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C. DEVENDRA

SUMMARY

The energy requirement for maintenance of pen-fed adult indigenous sheep is reported. This is based on data from 51 digestibility trials involving 671 sets of data which included the main daily intake of digestible organic matter (D), mean live weight (W) and the mean daily change in live weight (G). Calculation of the mean maintenance requirement was achieved from the general formula D : a Wk + b G. The data was first grouped into three categories: G : 0, -ve or +ve and calculations made of k, the exponent relating body weight to surface area, but statistically significant differences (P<0.01) were found between these. The mean values and ranges of the values were W = 21.6 kg (15.5 - 27.7 kg) and G = -0.02 (-0.5 - +0.5 kg). Since an accurate calculation of maintenance is best established when G = 0 in energy equilibrium, the corresponding equation was found to be D = 0.0301 W0.748 + 0.012 G (± 0.033). It was calculated that the mean maintenance requirements was 471.8 KJ ME/0.75kg/day. This value falls within the range of several values reported for sheep in temperate environments and is approximately similar to the value of 471.8 KJ ME/0.75kg/day reported for tropical sheep in the West Indies. It is stressed that under grazing conditions outdoors, the maintenance requirements would be considerably higher, and remains to be determined. Practical recommendations are given for indigenous sheep in Malaysia in a table of maintenance requirements in the body weight range 15 - 40 kg.

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THE PERFORMANCE OF KEDAH-KELANTAN CATTLE FED WITH PELLETED PINEAPPLE BRAN RATION

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MOHD. SUKRI HJ. IDRIS

SUMMARY

Two performance trials were conducted at MARDI Research Station, Kluang to study the growth and economic performances of beef cattle fed with copra cake or palm kernel cake rations containing pelleted pineapple bran at 30% or 55% levels. It was found that copra cake ration incorporated with 55% pineapple bran was more efficient than the other ration in producing better average daily gain and feed efficiency. Increasing the level of pineapple bran from 30% to 55% in the palm kernel cake ration had produced no significant effect on the animal performance. It was also found that supplementing these feeds with a 3-hour-per-day grazing allowance in the second trial proved not to be beneficial since it reduced feed efficiency and increased cost per kilogram liveweight gain of all groups.

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PRELIMINARY STUDY ON VITAMIN E AND SELENIUM SUPPLEMENTATION IN DIETS FOR GROWING-FINISHING PIGS

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C.H. PHUAH, R. JIKEN, S.P. SOO and J.J. ROCH

SUMMARY

Forty-five piglets were used to study the effect of supplementation of 3 levels of vitamin E (0, 10 and 20 mg/kg) in combination with 3 levels of Se (0, 0.1 and 0.2 ppm). No significant differences in final bodyweight, daily gain and feed conversion efficiency can be attributed to the main effects of vitamin E and Se supplementation. The interaction between vitamin E and Se is evident only in the final bodyweight (P<0.05), daily gain (P<0.01) and feed conversion efficiency (P<0.01). The carcass traits including meat colour were not significantly affected by the supplementation of vitamin E and/or Se.

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COMPARISON OF IODINE VALUES (IV) OF CRUDE PALM OIL FROM GLC CALCULATIONS WITH THOSE FROM WIJS METHOD

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A.H.G. CHIN and W.L. SIEW

SUMMARY

Iodine values (IV; ranging from 50 - 55) of crude palm oil determined by titration (Wijs method) were compared with ìwo different sets of calculated IV's derived from fatty acid composition (FAC) by gas chromatography (GLC). The calculated values were obtained by using two sets of factors, one based on the fatty acid molecular weights and the other based on the methyl ester molecular weights. Statistical analysis of the results obtained showed that the latter gave IV's which were better correlated with the IV's by the Wijs method. A relationship of y = 0.46x + 28.98 where y is the expected IV by Wijs method and x is the calculated IV using FAME factors, has been shown to give good fit with observed values.

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Journal of Tropical Agriculture and Food Science (JTAFS)
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