Category Archives: Volume 4 No. 4 (1982)

Biology of the Coconut Two-Colored Beetle, Plesispa reichei Chapuis


Author(s): Violeta S. Panggoy and Lorenza B. de Pedro

Abstract

The coconut two-colored beetle, Plesispa reichei. Chapuis, underwent 4 developmental stages, namely; egg, larva, pupa and adult. The larval stage had 4 instars with a total developmental period of 49.66 days for the females and 45.11 days for the males. An adult female laid an average of 64.28 eggs at the rate of 1 to 2 eggs per day. The egg is elongate and rounded at both ends. The larva is carabiform while the pupa is exarate. The adult male and female beetles can be differentiated through the depression at the center along the margin of the last abdominal segment which is more prominent in the male than in the female. The beetle can complete its development on the alternate hosts Borrasus flabellifera, Acloniclla merilli and Caryota curningii.

Keywords : Plesispa reichei. Coconut insect pest. Development. Morphology. Host range.

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Chemical and Biochemical Evaluation of Some Local Foodstuffs


Author(s): Lydia A. Gloria, Fe C. Abogadie, Carolina M. Bermoy, Felix M. Salas, Ana Gina T. Sembrano
and Elizabeth M. Sombilon

Abstract

The nutrient and protein content of 15 local foodstuffs were chemically and biologically evaluated. Plant proteins were found to be inferior in quantity and quality especially in terms of their protein digestibility and amino acid utilization. These were attributed to such factors as presence of toxins, high fiber content and amino acid deficiency or imbalance. For better utilization, it was suggested that proper cooking be done to counteract the heat-correctable factors. The mixture of different proteins in the diet was also recommended to correct the amino acid deficiency or imbalance.

Keywords : Bio-chemical evaluation. Nutrient composition. Food-stuffs.

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Varietal Reaction of Coconut to Oligonychus velascoi Rimand, Using Five Mite-Based Biological Parameters


Author(s): Merlene B. Capuno and Lorenza B. de Pedro

Abstract

Five mite-based biological parameters were used to determine the effect of the coconut varieties Baybay Tall, Malayan Orange Dwarf (MOD) and MAWA on the biology of spider mite Oligonychus velascoi Rimando. Parameters like total developmental period, fecundity of females and adult longevity indicated that Baybay Tall was the most suitable host for spider mites. On the other hand. MOD seedlings were unsuitable to the mites. A high mortality of immatures was noted in MOD, suggesting the presence of antibiotic component in its sap. An intermediate suitability of immatures was observed in MAWA hybrid seedlings. The prescribed minimum number of seedlings for assessing varietal reaction of pests differed with the coconut varieties used and the biological parameters considered.

Keywords : Coconut. Varietal reaction. Oligonychus velascoi. Mite.

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Effect of Cultural Practices in the Control of Collar Rot Infection in Coffee Seedlings


Author(s): P. Venkatasubbaiah and K. M. Safeeulla

Abstract

Incorporation of sand in the soil influenced the disease severity of collar rot in coffee while lime significantly reduced the occurrence of the disease. Rice-straw mulching was found to increase the growth and degree of infection of R. solani while exposing the seedbeds without mulching was found unsuitable for seed germination. The percent seed germination increased and disease severity was considerably reduced when seedbeds were covered with polythene sheets. Irrigation of seedbeds at different intervals did not significantly affect seed germination and mortality of coffee seedlings due to collar rot. However, plants which received water once in 24 hr were slightly vigorous than those which received water once in 48 hr.

Keywords : Soil composition. Mulching. Irrigation. Behavioral influence. Collar rot. Rhizoctonia solani. Coffee.

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Biology of the Black Leafhopper, Ricania speculum Walker on Patola (Luffa cylindrica (L) Roem)


Author(s): Alejandro D. Solis and Nelson Esguerra

Abstract

Eggs of black leafhopper, Ricania speculum Walker, were laid in batches on the nether surface of patola leaves (Luffa clyindrica (L) Roem) and were commonly covered with white mealy secretions. Incubation period of eggs on both detached and undetached leaves lasted 17 days. Total development period ranged from 40-71 days for males and 37-73 days for females when reared on detached leaves, and 41-61 days for males and 40-61 days for females on undetached leaves. There were 5 nymphal instars. The male to female ratio was 1:1.32 for those reared on detached leaves. Of the 5 alternate hosts tested, ampalaya (Momordica charantia L.) sustained the insects for the longest period, i.e., until the 4th instar. An identified species of spider preyed on both the nymphs and adults

Keywords : Black leafhopper. Ricania speculum Walker. Mass reading. Patola. Luffa clyindrica. Life history and behavior. Host range. Natural enemy.

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Morphological Effects of Naphthalic Anhydride And/Or Thiobencarb on IR-36 and RD-19 Rice Seedlings


Author: Rolinda L. Talatala

Abstract

The root and shoot elongation as well as the anatomy of IR-36 and RD-19 rice seedlings treated with different concentrations of NA (1,8- naphthalic anhydride), thiobencarb (S-4-chlorobenzyl diethylthlocarba-mate) and NA + thiobencarb was observed. Root elongation in the 2 cultivars was adversely affected by thiobencarb but not by NA treatment. Generally. the presence of NA in antidote-herbicide treatments seemed to reduce the inhibitory effect of thiobencarb on the root. Shoot growth was inhibited by thiobencarb and NA thiobencarb to a greater extent than root growth. Inhibition of root and shoot elongation was more pronounced in IR-36 than in RD-19 seedlings. Root growth inhibition by thiobencarb was not accompanied by any phytotoxic symptom at the histological level. In the shoot. thiobencarb injury was expressed by kinking of linear rows of cells and alteration of physical arrangement of mesophyll cells in develop-ing leaves within the coleoptite. This anatomical effect was noted in all thiobencarb treatments with or without NA in both cultivars except in the NA + 5 ppm thiobencarb treatment on RD-19 seedlings. Such anatomical observation can be correlated with the abnormal growth and emergence of leaves from grass coleoptiles which are the major phytotoxic symptoms induced by thiobencarb and other thiocarbarnate herbicides.

Keywords : Morphological effects. Naphthalic anhydride. Thiobencarb. Anatomy. Rice seedlings. Root. Shoot. Kinking. Elonga-tion. Coleoptile.

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Fungicidal Seed Treatment and Foliar Spray in Relation to Rhizoctonia solani Infection in Coffee


Author(s): P. Venkatasubbaiah, K.M. Safeeulla and M. Satishchandra Prabhu

Abstract

In vitro seed treatment with carboxin, carbendazirn, benomyl, guinto-zene. triadimefon and thiophanate-methyl enhanced the percent germina-tion of Coffea arabica and C. canephora. The percentage of seed germina-tion and the relative growth of hypocotyl were closely related to the con-centration of the fungicide used. There were no phytotoxic symptoms in the seedlings obtained from the treated seeds except those treated with triadimefon. Either seed treatment or foliar spray of the fungicides generally reduced Rhizoctonia solani infection in vitro. Of the fungicides used carboxin either as seed dressing or foliar spray gave the most promising results followed by thiophanate-rnethyl and carbendazim.

Keywords : Fungicide. Differential application. Phytotoxicity. Coffee. Percent infection. Collar rot. Rhizoctonia solani.

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Effects of Water Temperature on the Early Growth and Development of Taro


Author(s): J. R. Pardales, Jr., F.M. Melchor and R.S. de la Peña

Abstract

Taro (Colocasia esculenta (L) Schott) plants exposed to 28°C water temperature exhibited better plant growth and leaf area development, more and longer roots and higher dry matter content than those grown at other water temperature, i.e., 18-22°C (normal) and 37°C. Inferior vegetative growth and least and shortest roots were noted in plants grown at 37°C. In a follow-up experiment conducted using 2 taro varieties, production of higher number and significantly longest roots was found to be greatly favored by a temperature range of 27-29°C. Reduction in both number and length of roots occurred when temperature became higher but drastic effect of temperature was very apparent at 36-38°C. Temperature beyond 29°C seemed to be detrimental to root growth in newly planted taro. At 36-38°C, roots of the 2 varieties used did not grow beyond 2 cm.

Keywords : Taro Colocasia esculenta. Bun Long. Lehua Maoli. Water temperature. Vegetative development. Root development. Initial growth.

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