Industrial Crops
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Browsing Industrial Crops by Author "Abassa, R.O."
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Item Laboratory Studies of the Biology and Food Requirements of Macrorhaphis Acuta Hemiptera : Pentatomidae)(1974) Abassa, R.O.; Mathenge, W.M.Macrorhaphis acuta were bred in the laboratory (25°C) and fed on larvae ofAscotis selenaria reciprocaria. The incubation period was 8.4 days and the mean hatch was 94.4%. There were 5 nymphal instars which occupied 3.3, 5.0, 5.6, 6.6 and 12.0 days, respectively, from the lst to the 5th. Each nymph consumed an average of 22.8 host larvae to complete development. Adults had a mean longevity of 74.9 days and each consumed an average of 67.5 host larvae. Significant reduction was noted in pupation of 5th instar host larvae sucked by adult predators for periods ranging from 4 to 10 mn. The food requirements of 3rd, 4th, and 5th instar nymphs fed on 3rd instar host larvae were also investigated. The conversion ratio varied with the weight of food consumed during the instar and later instars were more efficient than earlier ones. Predatory value did not vary significantly with successive instars.Item Observations on the Seasonal Emergence Of fruit Flies on a Kenya Coffee Estate and Studies of the Pest Status of Ceratitis Capitata Wied in Coffee(1973) Abassa, R.O.Neither the distribution nor the economic importance of Trypetid flies has been investigated on Kenya coffee estates. Laboratory studies have shown that female Mediterranean fruit flies, Ceratitis capitata Wied Puncture the coffee berry skin with the aid of the ovipositor and deposit eggs inside immature soft beans or under the skin of mature berries (Abasa 1972). The larva feeds on pulp below the skin layer until at maturity it either pupates between the ripe beans or it drops to the ground in the mulch or in the soil to pupate. Larvae that hatch from eggs laid in immature or hardened green berries die before reaching maturity ( McCrae 1956).Item Observations on the seasonal emergence of fruit flies on a Kenya Coffee estate and studies of the pest status of Ceratitis capitata wied in Coffee(1973) Abassa, R.O.; International Red Locust Control OrganizationStudies of seasonal emergence of fruit flies breeding in coffee at the Coffee Research Station, Ruiru, showed that C. capitata breeds throughout the year without distinct generations. C. rosa and T. cofeae were far less abundant during a 2-year period and showed no clear seasonality. Attempts to induce stinkers in coffee liquor using C. capitata gave negative results. Neither the colour, quality, acidity, body, flavour, nor final classification of berries infested with larvae were affected. Tests to induce premature berry fall by C. capitata indicated that an average of 2.8 per cent of berries attacked by C. capitata Would fall prematurely compared with 0.26 per cent which fell prematurely due to natural causes.Item The Praying Mantis, Sphodramantis Sp. as a Predator of the Giant Looper, Ascotis Selenaria Reciprocaria Walk In Kenya Coffee: Laboratory Evaluation(1979) Abassa, R.O.; Mathenge, W.M.Mantids are general predators and will feed on almost any insect smaller than themselves. Among the preferred food are flies, grasshoppers and caterpillars. Larger mantids are, in addition, cannibalistic on the smaller mantids. It is probably due to this behavior that mantids are usually solitary, staying motionle5S for a long time while waiting for an unsuspecting potential prey to come close. Their eggs are laid in specially constructed egg pods (oothecae) which are attached to twigs, bark or other objects (Plate I). It is common to find oothecae attached to coffee tree stems, branches and twigs. When mantids are reared in the laboratory, however, oothecae are glued to the walls of cages. On opening an ootheca, eggs are found arranged in rows and enveloped in a firm spongy substance. The incubation period varies with each species. Those of Sphodromantis viridis Forst hatch in 20-25 days under laboratory conditions (25 -+- 1°C, 65 ± 5 per cent R.H.). The number of nymphs from a single ootheca varies with the species but is often greater than 25. Development to adult stage is rather slow and may be prolonged to 12 months in some European species. Our laboratory observations, although incomplete, show that S. viridis undergoes at least six moults before becoming adult. Each stadium (the period between moults in a developing insect) occupies 16-19 days.Item The Praying Mantis, Sphodramantis Sp. as a Predator of the Giant Looper, Ascotis Selenaria Reciprocaria Walk In Kenya Coffee: Laboratory Evaluation(1971) Abassa, R.O.; Mathenge, W.M.Their eggs are laid in specially constructed eggpods (oothecae) which are attached to twigs, bark or other objects (Plate I). It is common to find oot hecae attached to coffee tree stems,bralliChes and twigs. When mantis are reared in the laboratory, however, oothecae are glued to the walls of cages. On opening an ootheca, eggs are found arranged in rows and enveloped in a firm spongy substance. The incubation period varies with each species. Those of Sphodromantis viridis Forst hatch in 20-25 days under laboratory conditions (25 -+- 1 •C, 65 ± 5 per cent R.H.). The number of nymphs from a single ootheca varies with the species but is often greater than 25. Development to adult stage is rather slow and may be prolonged to 12 months in some European species. Our laboratory observations, although incomplete, show that S. viridis undergoes at least six moults before becoming adult. Each stadium (the period between moults in a developing insect) occupies 16-19 days.Item A Review of The Biological Control Of Coffee Insect Pests In Kenya(1975) Abassa, R.O.There is no universal agreement on what is covered by the term "biological control" although it is generally agreed to mean reductions of populations of living organisms by other living organisms. In most definitions, however, the planned and deliberate participation by man in initiating, maintaining or encouraging this process is stated or, at least, implied. Some authors [59] restrict the definition to the action of parasites predators or pathogens "applied regardless of whether or not man deliberately introduces, manipulates or modifies the biological control agents". Hinton [31], on the other hand, restricted the definition to attempts in which the objective is permanent control while Sweet man [60] extended the terms to include the use of antibiotics and resistant strains of plants. The use of sterilized males of pest species [37, 47], lethal genetic strains of pest species [16] and of non pest species that drive out pest species by competition [10] have also been considered to be biological control.
