Category Archives: Volume 2 No. 2 (1980)

Varying lnoculum Levels of Bacteria-Nematodes and the Severity of Tomato Bacterial Wilt


Author: C. M. Napiere

Abstract

Development of bacterial wilt was consistently earlier on plants inoculated with both bacterium (Pseudomonas solanacearum E.F. Smith) and nematode Meloidogyne incognita Chitwood) compared to those inoculated with the bacterium alone. The percentage mortality also increased with increasing nematode population in the bacterium-infested soil. The presence of M. incognita enhanced the development and severity of bacterial wilt and lowered the yield of wilt-resistant tomato cultivars.

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Effects of Ipil-lpil and Ammonium Sulfate As Nitrogen Sources of Sweet Potato


Author(s): Leonila A. Urdaneta and Reynaldo R. Javier

Abstract

Nitrogen application, either with the use of ammonium sulfate or ipil-ipil leaves, significantly improved the yield and yield components of the three varieties of sweet potato. except in the number of non-marketable tubers. Among the varieties tested, BNAS-51 yielded the highest amount of marketable tubers with an average of 11.1 t/ha, followed by Bakabakahan and Bulacan with 8.03 and 6.6 t/ha, respective!). BNAS-51 and Bakabakahan produced more and heavier marketable tubers/plant, and longer and heavier fresh weight of vines/plant. BNAS-51 had fewer but heavier non-marketable tubers than the other two varieties. Plants which received nitrogen (N) from ipil-ipil leaves produced more and heavier fresh vines/plant than those without N. A lower percentage of dry matter content was observed in N-fertilized plants. In terms of tuber yield, plants which received 60 kg/ha, either from ipil-ipil leaves or ammonium sulfate, yielded more with 3.0 and 6.0 t/ha, respectively, than those plants which did not receive N. Despite the equal rates of N application, plants which were applied with inorganic N fertilizer (ammonium sulfate) Produced significantly higher yields than plants which received organic fertilizer (ipil-ipil leaves).

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Sweet Potato Tuber Rot Disease in the Philippines


Author(s): M. K. Palomar, A. D. Solis and H. S. Bandala

Abstract

Tuber rot or Java black rot, caused by Diplodia theobromae (Pat.) Nowell is the most prevalent storage disease of sweet potato. Affected tubers become dry, hard and coal-black in color. Isolations made from stored sweet potato revealed a high incidence (69%) of D. theobromae alone and in combination with other fungi. The occurrence of Aspergillus, Rhizopus and Fusarium in tubers was limited. D. theobromae was artificially inoculated to healthy tubers from field-planted sweet potato accessions. BNAS-51 variety was used as check throughout the experiment. Preliminary results indicate that 78 cultivars were resistant, 13 were moderately resistant and 78 were susceptible to tuber rot.

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Growth and Yield of Sorghum as Influenced by Green Manure and Soil Organic Matter Content


Author(s): R. B. Capuno, B. E. Fabre and R. G. Escalade

Abstract

Green manure increased the organic matter content of the soil. Soybeans, as green manure, provided the highest organic matter content (3.796%), followed by mungbean (3.268%) and bushbean (2.836%). The plot without green manure had the lowest organic matter content of 1.740%. The nutrients from the organic matter of the soil significantly increased plant height in the treated plots more than those in plots without green manure. This practice was not effective in increasing the panicle length, panicle weight, and the 100-grain weight of sorghum. Using mungbean as green manure significantly decreased the grain yield of sorghum although there was a significant increase in plant height. Highly significant differences were observed on the effects of the inorganic fertilizer treatments. Application of 30-30-30 kg/ha of N, P205, and 1{20 markedly increased plant height, leaf area index, panicle length, panicle weight, and grain yield (2.24 t/ha). Plots where no fertilizer was applied yielded 1.12 t/ha of grain.

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Structure and Diversity of Arthropods at Wahila Ridge, Hawaii


Author(s): Nelson M. Esguerra and Patrick R. Jackson

Abstract

Arthropod populations and their structure in soil and litter at three elevations were studied at Wahila Ridge, Hawaii. Berlese funnel was used to extract the fauna from soil and litter samples. More species and higher population of arthropods were recovered in stream soil and litter than in soil and litter at middle and hill elevations. It was probable that during dry conditions, most of the arthropods died and/or aestivated and became active again as soon as vegetation and litter became abundant. During the second sampling, there was a greater number of species and population of arthropods than in the first and third samplings, the greatest number of arthropods occurring in stream soil and litter. The arthropod populations in stream soil and litter were more diverse, had lower index of dominance, but showed more evenness, similarity and richness compared to those on the hill and middle elevations. Species and populations of arthropods in soil and litter were affected by weather.

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Response of Coconut Seedlings to Spacing and Application of Nitrogen and Potassium


Author(s): Eufemia A. Almaden and Rebecco M. Santiago

Abstract

Significant variations in the effects of spacing were observed on the vegetative growth and overall vigor of coconut seedlings in the nursery. Plants grown at a distance of 40 cm and farther (60 and 80 cm) had bigger girth diameter, more split leaves, and greater vigor index value than plants grown at 30 cm apart. Similarly, nitrogen-potassium application exerted a significant influence on the vegetative growth of coconut seedlings. All plants applied with inorganic fertilizer, irrespective of the rate, were taller, had bigger girth diameter, and greater vigor index value than those which did not receive fertilizer. There were no significant interaction effects of nitrogen-potassium application and spacing on all parameters considered.

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Stems and Tubers for Rearing Sweet Potato Weevil


Author(s): E. A. Vasquez and D. P. Gapasin

Abstract

Sweet potato weevil, Cylas formicarius elegantulus Fabr. was successfully reared on mature stems using longitudinal halves and on tubers using thin chips held between plastic rearing blocks. There were no differences in size and behavior of larvae, pupae and adults but there was only slight difference in duration of life cycle and mortality of weevils reared on tubers and mature stems. Results show that mature stems were as suitable as tubers in rearing sweet potato weevil. However, the use of tuber chips was the most suitable and economical method of rearing sweet potato weevil in the laboratory.

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Residual Nitrogen From Legumes and Its Effect on the Succeeding Crop of Sweet Potato


Author(s): Antonio L. Acedo, Jr. and Reynaldo R. Javier

Abstract

Three legumes (mungbean, bushbean, and soybean) and sweet potato (control) were planted during the first cropping. After harvesting each crop, the residues except those of sweet potato were plowed under and incorporated into soil. The final planting of sweet potato was done subsequently after the legume the residues had been decomposed. Results showed that there was a significant increase in the weight and length of vines of the three legumes. Weight and number of marketable tubers, weight of non-marketable tubers, and total tuber yield greatly increased in plots previously planted to bushbeans and soybeans while the said parameters had no effect on mungbeans. Tuber yield and other agronomic characters were positively influenced by the different fertilizer levels. Fertilizer level of 0-3040 kg/ha increased considerably the tuber yield of sweet potato planted after bushbeans or soybeans. Cost and returns analysis revealed that, regardless of the level of fertilizer applied, higher net profits were obtained from plots previously planted to bushbeans and soybeans. The best result was noted in the continuous sweet potato cropping treated with 60-60-60 kg/ha on both croppings. Considering net returns per unit time, however, alternate cropping of sweet potato with bushbeans or soybeans gave greater output in addition to the improved physical conditions of the soil.

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Acceptability of Cured Duck Meat Using A New Method


Author: L. S. Palomar

Abstract

Muscovy duck and native chicken were used to compare the acceptability of smoked duck cured at 2 vs 3 days, 55° vs 70° salinity and with vs without refrigeration in a clay pot. Results indicate that 2-day curing is better than 3-day curing in smoked duck with 55° salinity. It is therefore important when curing meat, especially poultry, that quantitative measurements and time schedule be observed. Clay pot seems to be an acceptable curing container since samples were as acceptable as those cured in the refrigerator. Comparison and hedonic scale tests indicate that clay pot has a temperature sufficiently low to retard most bacterial growth until salt penetration is complete. In addition, cured duck was as acceptable as cured chicken based on the scores given in different sensory qualities evaluated such as color, flavor, off-flavor, saltiness, tenderness, juiciness and general acceptability.

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