Agricultural Science Commons^™

Diel Periodicity In The Production Of Green Leaf Volatiles By Wild And Cultivated Host Plants Of Stemborer Moths, Chilo Partellus And Busseola Fusca, K. Chamberlain, Z. R. Khan, J. A. Pickett, T. Toshova, L. J. Wadhams

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The volatile chemicals produced by four poaceous plant species, blue thatching grass, Hyparrhenia tamba, Napier grass, Pennisetum purpureum, sorghum, Sorghum bicolor, and maize, Zea mays, which are host plants for the lepidopterous stemborers, Chilo partellus and Busseola fusca, were collected by air entrainment and analyzed by gas chromatography. The total quantities of volatiles collected hourly, over a 9-hr period, from P. purpureum and H. tamba showed an approximately hundredfold increase in the first hour of the scotophase. Thereafter, the amount decreased rapidly to levels present during photophase. Although onset of scotophase also triggered an increase in quantities of volatiles collected …

The Effect Of Nitrogen Fertilizer Application To Maize And Sorghum On The Bionomics Of Chilo Partellus (Lepidoptera: Crambidae) And The Performance Of Its Larval Parasitoid Cotesia Flavipes (Hymenoptera: Braconidae), N. Jiang, F. Schulthess

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Laboratory and field trials were conducted to evaluate the effect of plant species (maize, sorghum), plant age (young, middle, old) and four different nitrogen fertilization levels (N0-N3) on the bionomics of the invasive crambid Chilo partellus and the performance of its braconid larval parasitoid Cotesia flavipes. Plant N varied significantly between N0 and N1-N3, but the differences among the latter were not significant. Intrinsic rates of increase and net-reproductive rates of C. partellus followed the same trends: they were lowest with N0 and similar among the other treatments. On maize only, mortality of C. partellus and parasitism by C. flavipes …

Relationships Of Intercropped Maize, Stem Borer Damage To Maize Yield And Land-Use Efficiency In The Humid Forest Of Cameroon, A. Chabi-Olaye, C. Nolte, F. Schulthess, C. Borgemeister

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Stem borers are the most important maize pests in the humid forest zone of Cameroon. Field trials were conducted in the long and short rainy seasons of 2002 and 2003 to assess the level of damage and yield reductions caused by stem borers in monocropped maize and in maize intercropped with non-host plants such as cassava, cowpea and soybean. The intercrops were planted in two spatial arrangements, i.e. alternating hills or alternating rows. All intercrops and the maize monocrop were grown with and without insecticide treatment for assessment of maize yield loss due to borer attacks. The land-use efficiency of …

Effects Of Grain Legumes And Cover Crops On Maize Yield And Plant Damage By Busseola Fusca (Fuller) (Lepidoptera: Noctuidae) In The Humid Forest Of Southern Cameroon, A. Chabi-Olaye, C. Nolte, F. Schulthess, C. Borgemeister

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Field trials were run in the humid forest zone of Cameroon to investigate the effects of crop rotation, cover crops and bush fallow on infestations by the noctuid stemborer Busseola fusca (Fuller) and on yield of maize. A continuous maize production system was compared with crop sequence systems, in which maize followed a grain legume (cowpea, soybean), cover crop (mucuna, pigeon pea) or a bush fallow. Compared to the continuous maize cropping system, maize in the crop sequence with legume and fallow systems had significantly higher leaf and stem nitrogen content at 35 and 63 days after planting (DAP), respectively. …

Life Tables, Key Factor Analysis And Density Relations Of Natural Populations Of The Spotted Maize Stemborer, Chilo Partellus (Lepidoptera: Crambidae), Under Different Cropping Systems At The Kenyan Coast, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt

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Studies were conducted at Mtwapa, in the coastal area of Kenya, during the long and short rains of 1999 and 2000 to evaluate interaction of mortality factors in lowering Chilo partellus (Swinhoe) populations in diverse agroecosystems. Treatments consisted of hedgerows of leucaena only, gliricidia only, alternating rows of leucaena and gliricidia, and three plots without trees. During the cropping seasons, maize was planted between the hedgerows while a row of cowpea was planted between the rows of maize. One of the plots without trees was planted to an intercrop of maize and cowpea. The remaining two plots without trees were …

Comparative Performance Of The Mbita Trap, Cdc Light Trap And The Human Landing Catch In The Sampling Of Anopheles Arabiensis, An. Funestus And Culicine Species In A Rice Irrigation In Western Kenya, Evan M. Mathenge, Gedion O. Misiani, David O. Oulo, Lucy W. Irungu, Paul N. Ndegwa, Tom A. Smith, Gerry F. Killeen, Bart G.J. Knols

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Background: Mosquitoes sampling is an important component in malaria control. However, most of the methods used have several shortcomings and hence there is a need to develop and calibrate new methods. The Mbita trap for capturing host-seeking mosquitoes was recently developed and successfully tested in Kenya. However, the Mbita trap is less effective at catching outdoor-biting Anopheles funestus and Anopheles arabiensis in Madagascar and, thus, there is need to further evaluate this trap in diverse epidemiological settings. This study reports a field evaluation of the Mbita trap in a rice irrigation scheme in Kenya. Methods: The mosquito sampling efficiency of …

Effect Of Agroecosystem Diversity On Natural Enemies Of Maize Stemborers In Coastal Kenya, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt

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A study was conducted at Mtwapa in the northern coastal area of Kenya during the long and short rainy seasons of 1999 and 2000 to assess the benefits of agroecosystem diversification-through agroforestry and intercropping-on the activity of natural enemies of maize stemborers. Treatments consisted of maize and cowpea intercrops or maize monocrops planted within hedgerows of Leucaena leucocephala and Gliricidia sepium. The plots were mulched or unmulched and insecticide-treated or not. The maize stemborers encountered, in order of abundance, were Chilo partellus, Chilo orichalcociliellus and Sesamia calamistis. The egg parasitoids Trichogramma spp. and Telenomus spp. were recovered from stemborer eggs. …

Multi-Trophic Level Interactions In A Cassava-Maize Mixed Cropping System In The Humid Tropics Of West Africa, F. Schulthess, A. Chabi-Olaye, S. Gounou

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Multi-trophic level interactions in a mixed crop, involving cassava and maize, were studied in derived-savanna in Benin, West Africa. Two trials were planted, one during the short rainy season two months before onset of the dry season and one during the long rainy season in spring. Key pests under study on maize were the noctuid Sesamia calamistis Hampson and the pyralids Eldana saccharina Walker and Mussidia nigrivenella Ragonot, and on cassava, the exotic mealybug, Phenacoccus manihoti Matile-Ferrero and its encyrtid parasitoid Apoanagyrus lopezi De Santis. Both crops received insecticide treatments to assess the crop loss by a pest species. On …

Effect Of Constant Temperatures On Germination, Radial Growth And Virulence Of Metarhizium Anisopliae To Three Species Of African Tephritid Fruit Flies, Susan Dimbi, Nguya K. Maniania, Slawomir A. Lux, Jones M. Mueke

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The effect of temperature on conidial germination, mycelial growth, and susceptibility of adults of three tephritid fruit flies, Ceratitis capitata (Wiedemann), C. fasciventris (Bezzi) and C. cosyra (Walker) to six isolates of Metarhizium anisopliae were studied in the laboratory. There were significant differences among the isolates in the effect of temperature on both germination and growth. Over 80% of conidia germinated at 20, 25 and 30°C, while between 26 and 67% conidia germinated at 35°C and less than 10% at 15°C within 24 hours. Radial growth was slow at 15°C and 35°C with all of the isolates. The optimum temperature …

Effects Of Molasses Grass, Melinis Minutiflora Volatiles On The Foraging Behavior Of The Cereal Stemborer Parasitoid, Cotesia Sesamiae, Linnet S. Gohole, William A. Overholt, Zeyaur R. Khan, John A. Pickett, Louise E.M. Vet

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Olfactory responses of the cereal stemborer parasitoid Cotesia sesamiae to volatiles emitted by gramineous host and nonhost plants of the stemborers were studied in a Y-tube olfactometer. The host plants were maize (Zea mays) and sorghum (Sorghum bicolor), while the nonhost plant was molasses grass (Melinis minutiflora). In single-choice tests, females of C. sesamiae chose volatiles from infested and uninfested host plants and molasses grass over volatiles from the control (soil). In dual-choice tests, the wasp preferred volatiles from infested host plants to those from uninfested host plants. There was no discrimination between molasses grass volatiles and those of uninfested …

Comparative Life Table Statistics Of Exochomus Flaviventris Reared On The Cassava Mealybug, Phenacoccus Manihoti, Fed On Four Host Plants, B. P. Le Rü, A. Mitsipa

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The demographic statistics of the ladybird Exochomus flaviventris Mader (Coleoptera: Coccinellidae) were investigated under laboratory conditions on the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Homoptera: Pseudococcidae), reared on four host plants with different levels of antibiotic resistance to the mealybug: two cassava (Manihot esculenta Crantz, Euphorbiaceae) varieties, Incoza and Zanaga, Faux-Caoutchouc (FC) (hybrid of M. esculenta x M. glaziovii Muel. Arg.) and water weed (Talinum triangulare Jack, Portulacacae). Preimaginal mortality, mean oviposition time and total fecundity of female ladybirds were strongly affected by the host plant even though there was no linkage with antibiotic resistance. The net reproduction rates R o …

Density Effects Of The Banana Weevil, Cosmopolites Sordidus (Germar), On Its Oviposition Performance And Egg And Larval Survivorship, Clifford S. Gold, Godfrey H. Kagezi, Pontiano Nemeye, Philip E. Ragama

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The influence of banana weevil, Cosmopolites sordidus (Germar)(Coleoptera: Curculionidae), population density on oviposition rates and larval survivorship was studied in the laboratory at the Kawanda Agricultural Research Institute in Uganda. This study was undertaken to elucidate the relationship between density-dependent factors and rates of banana weevil increase in the field. Oviposition substrates (corm pieces) were offered to a range of densities of weevils maintained in buckets. Mean oviposition rates per female at densities of 10, 20 and 40 females per bucket were 29, 37 and 53%, respectively, lower than that at a density of 5 females. Nevertheless, total oviposition for …

Predators Of Mesoplatys Ochroptera In Sesbania Planted-Fallows In Eastern Zambia, G. Sileshi, M. Kenis, C. K.P.O. Ogol, S. Sithanantham

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Mesoplatys ochroptera Stål (Coleoptera: Chrysomelidae) is a serious pest of the tropical legume sesbania (Sesbania sesban (L.) Merrill) widely used for soil fertility improvement in southern Africa. Surveys were conducted between October 1997 and June 1999 in order to identify the predators of M. ochroptera in sesbania fallows in eastern Zambia. The Heteroptera Afrius yolofa (Guérin-Méneville), Glypsus conspicuus (Westwood), Macrorhaphis acuta Dallas, Mecosoma mensor (Germar), Rhinocoris segmentarius (Germar), and Deraeocoris ostentans (Stål), the carabid beetle Cyaneodinodes fasciger (Chaudoir), the ants Tetramorium sericeiventre Emery and Pheidole sp., and the lacewing Mallada sp. were recorded as predators of M. ochroptera for the …

Impact Of Solar Radiation Rainfall And Cannibalism On Disappearance Of Maize Stemborers In Kenya, M. J. Bonhof, W. A. Overholt

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The effect of solar radiation, rainfall and cannibalism on the disappearance of eggs and larvae of the cereal stemborer Chilo partellus (Swinhoe) were studied. Disappearance and nonviability of egg batches was higher on plants exposed to solar radiation than on shaded plants. Significantly fewer small larvae were recovered from plants exposed to rainfall than from shielded plants. Cannibalism among larvae of the same size was not common except at high larval densities. Contrary to the common belief that disappearance is the result of prédation, these studies show that solar radiation and rainfall might also play an important role in the …

Greenhouse Trials Of New Bacillus Thuringiensis Isolates For Control Of Chilo Partellus Larvae In Sorghum, Michael Brownbridge

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Eight new Bacillus thuringiensis Berliner (Bt) isolates originally recovered from different source materials and geographic locations in Kenya were tested against Chilo partellus (Swinhoe) on sorghum grown in a greenhouse. All isolates had been demonstrated previously to be toxic to this pest. Bt strains were cultured in a liquid growth medium and preserved as powders for experimental application. Three-week-old sorghum plants (4-6 leaves) were artificially infested with 20 neonate C. partellus and sprayed 24 h later with Bt suspensions. Non-infested sorghum and infested non-treated sorghum served as the comparative checks within each experimental trial. Plant development and dead-heart formation were …

Distribution And Species Composition Of Stemborers And Their Natural Enemies In Maize And Sorghum In Ethiopia, Emana Getu, W. A. Overholt, E. Kairu

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Surveys were conducted to determine the species composition of stemborers and their natural enemies in maize and sorghum in 1999 and 2000 in eastern, northern, southern and western Ethiopia. The six species of stemborers found attacking maize and sorghum were Cltilp partellus (Swinhoe) (Lepidoptera: Crambidae), Busseolafiisca Fuller, Sesamia calamistis Hampson (Lepidoptera: Noctuidae), S. nonagrioides botanephaga Tarns and Bowden (Lepidoptera: Noctuidae), Rhynchaenus niger (Horn) (Coleoptera: Rhynchophoridae) and Pissodes dubious (Stroöm) (Coleoptera: Rhynchophoridae). Twenty species of primary parasitoids of eggs, larvae and pupae of Ch. partellus, B. fusca and S. calamistis were recorded. Other natural enemies, including predators, fungi and nematodes, were …

Relationships Of Stemborer Damage And Plant Physical Conditions To Maize Yield In A Semi-Arid Zone Of Eastern Kenya, Josephine Moraa Songa, Zhou Guofa, William Allan Overholt

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A field survey on maize stemborers, stemborer damage, maize plant physical conditions, and maize yield was conducted in eastern Kenya under natural conditions. Chilo partellus was the dominant stemborer accounting for 89.5 % of all borers. Stemborer damage greatly reduced maize yield, with tunnel lengths greater than 20 cm causing a 40 % reduction of potential yield. A 33 % yield loss was found in plants with more than one stemborer exit hole. Each stemborer (at harvest time) was correlated with a 8-10 % yield loss. Good plant physical characteristics significantly increased grain yield. Principle component analysis showed that stemborer …

Habitat Management Strategies For The Control Of Cereal Stemborers And Striga In Maize In Kenya, Z. R. Khan, J. A. Pickett, L. Wadhams, F. Muyekho

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Maize is the principal food and cash crop for millions of people in the predominantly mixed crop-livestock farming systems in Kenya. Stemborers and striga (Striga hermonthica) are major constraints to increased maize production in eastern Africa. An intercropping and trap crop system has been developed, using a ‘push-pull’ strategy, for the control of stemborers in small scale maize farming systems. The ‘push-pull’ strategy involves trapping stemborers on highly susceptible trap plants (pull) and driving them away from the crop using repellent intercrops (push). Napier grass (Pennisetum piirpiirenm Schumach) and Sudan grass (Sorghum vulgare sudanense Stapf J are used as trap …

Distribution And Abundance, In Maize And Sorghum, Of Lepidopteran Stemborers And Associated Indigenous Parasitoids In Zanzibar, E. I. Nlyibigira, Z. S. Abdallah, W. A. Overholt

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Studies to determine the relative abundance and distribution of stemborer species and their associated parasitoids in maize and sorghum were carried out during the 1995-1996 and 19992000 cropping seasons on Unguja and Pemba, the two main islands of Zanzibar. Three stemborer species were found on both islands in maize and sorghum, with the exotic species Chilo partellns (Swinhoe) (Crambidae) being the most abundant and widely distributed species, accounting for 75.3 % of stemborer attack. It was followed by Sesamia calamistis Hampson (Noctuidae) and C/i. oriclialcociliellus Strand (Crambidae). Stemborer abundance was significantly higher in Pemba (1.47 ± 0.20) than Unguja (0.85 …

Changes In The Distribution Of Lepidopteran Maize Stemborers In Kenya From The 1950s To 1990s, Zhou Guofa, William A. Overholt, Moses B. Mochiah

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Three hundred and ninety-two maize fields in the southern arable zone of Kenya were sampled for lepidopteran cereal stemborers from 1996-2000. Chilo partelhis (Swinhoe) was the most abundant stemborer, and was found at all locations with elevations below 1500 m, and at some locations between 1500 and 2300 m. The highest density of C. partelhis was in the semi-arid ecological zone of eastern Kenya. Chilo orichalcociliellus (Strand) was found in the lowland southern coastal area, and a few inland sites on the border of Tanzania in southeastern Kenya. Busseola fusca Fuller was dominant in highland areas. In the Lake Victoria …

Farmers’ Perceptions Of Importance, Control Methods And Natural Enemies Of Maize Stemborers At The Kenya Coast, M. J. Bonhof, A. Van Huis, F. G. Kiros, N. Dlbogo

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A survey among 240 resource-poor farmers at the Kenya coast indicated that insect pests were considered to be the main production constraint. Over 70% of respondents mentioned stemborers to be the most important insect pest. Unlike the eggs and adults, stemborer larvae and pupae were frequently seen by farmers. Alternative gramineous host plants for pests were common near maize fields and were often not destroyed until after the first rains. Nearly all farmers left dry stems and stubble in the field after harvest. Farmers knew of many methods for controlling stemborers, but only 32 and 56% of farmers in Kilifi …

Pathogenicity And Antifeedant Activity Of Entomopathogenic Hyphomycetes To The Cowpea Leaf Beetle, Ootheca Mutabilis Shalberg, S. Ekesi

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Conidial suspensions of four isolates each of Bcauvcria bassiana and Melnrhizhtm anisopliae were evaluated in the laboratory for their virulence to adult Ootlicca mntabilis. All the isolates tested were pathogenic to the beetle, but to varying degrees. Three of them, B. bassiana CPD 3 and CPD10 and M. anisopliae CPD 6 were superior to all other isolates in terms of mortality induced on adult beetle, LT50 and LC50, with B. bnssiana CPD 3 having the lowest LC50 value. In feeding assayi consumption by beetles treated with B. bnssiana CPD 3 was significantly reduced within 2 days treatment (DAT) and the …

Susceptibility Of The Legume Flower Thrips To Metarhizium Anisopliae On Different Varieties Of Cowpea, S. Ekesi, N. K. Maniania, W. Lwande

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The susceptibility of Megalurothrips sjostedti to Metarhizium anisopliae when reared on susceptible, tolerant, and moderately resistant varieties of cowpea at different constant temperatures was evaluated in the laboratory. Insects were exposed either to direct spray of the conidia or to fungus-treated floral tissues. Mortality was significantly higher on the moderately resistant variety at all temperatures compared to the susceptible and tolerant varieties. Correspondingly, lethal time and lethal concentration values were significantly shorter and lower, respectively, on the moderately resistant variety compared to the other varieties, thus indicating that the two control methods are compatible as part of an integrated pest …

Evaluation Of Banana Cultivars For Resistance To The Banana Weevil Cosmopolites Sordidus And Nematode Complex In Western Kenya, T. Musabyimana, K. V. Seshu Reddy, L. Ngode, J. S. Prasad

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Banana weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) and parasitic nematodes are often together on the same banana mat. Both pests have been recognized as major constraints to banana production. They may cause up to 85% yield loss in banana. Hence, both pests should be investigated together to define a control strategy for this complex constraint. With this view, our investigation was carried out in a naturally nematode-weevil infested farmer's field to search for host plant resistance to both pests. Pratylenchus goodeyi, Helicotylenchus multicinctus and Meloidogyne spp. were the most commonly occurring nematodes in the experiment and were often in mixed …

Powdered Neem Seed And Cake For Management Of The Banana Weevil, Cosmopolites Sordidus, And Parasitic Nematodes, T. Musabyimana, R. C. Saxena, E. W. Kairu, C. K.P.O. Ogol, Z. R. Khan

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Field trials were conducted in Kenya with 'Nakyetengu', an East African highland banana cultivar (AAA-EA), highly susceptible to banana pests. Regardless of soil fertility levels, incorporation around the plant base of powdered neem (Azadirachta indica A. Juss.) seed or cake at 60-100 g/mat at 4-month intervals, gave better control of the banana weevil, Cosmopolites sordidus (Germar), and of parasitic nematodes, than that achieved with soil application of Furadan 5G (carbofuran) at 60 g/mat at 6-month intervals. Compared with untreated control, fruit yield in most of the neem treatments was significantly higher, particularly during the second cycle of crop production. Neem …

Effect Of Volatiles And Crude Extracts Of Different Plant Materials On Egg Viability Of Maruca Vitrata And Clavigralla Tomentosicollis, S. Ekesi

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The effect of volatiles and aqueous extracts of black pepper, Piper guineense; neem seed, Azadirachta indica; garlic bulb, Allium sativum; and onion bulb, Allium cepa on egg viability of Maruca vitrata Fab. (Lepidoptera: Pyralidae) and Clavigralla tomentosicollis Stal (Heteroptera: Coreidae) was evaluated in laboratory experiments. Compared with the other treatments, volatiles of black pepper and garlic bulb were superior in reducing hatch of freshly laid (12-h-old) eggs of both species of insects. Volatiles of onion bulb and neem seed had no effect on egg hatch. When aqueous extracts of the various plant materials were tested at 5%, 10% and 15%, …

Bulletin 4385 - Control Of Mediterranean Fruit Fly (Medfly) In Commercial Orchards, Sonya Broughton, Francis De Lima

Bulletins 4000 -

The Mediterranean fruit fly (Medfly) is thought to originate from tropical Africa. It is a pest in many areas of the world including Western Australia. It was first detected at Claremont in 1895 and is now found as far south as Esperance and as far north as Derby. The main area of infestation extends from Carnarvon to Bunbury.

Medfly is known to infest over 200 fruit and vegetable species. In Western Australia, stone fruit, pome fruit, citrus, guavas, figs and loquats are particularly susceptible.

Selection Of Virulent Isolates Of Entomopathogenic Hyphomycetes Against Clavigralla Tomentosicollis Stål. And Evaluation In Cage Experiment Using Three Cowpea Varieties, S. Ekesi

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The virulence of 8 isolates of entomopathogenic hyphomycetes against adult and 5th instar nymph of Clavigralla tomentosicollis was evaluated in the laboratory at 4 different concentrations of inoculum. At all concentrations, Beauveria bassiana CPD 9 and Metarhizium anisopliae CPD 5 caused the highest mortality in adult bug ranging from 58 to 97% and 53 to 100%, respectively at 7 days post inoculation. The same isolates had the shortest LT50 (3.5 and 4.1 days, respectively) and the lowest LC50 (1.8 × 105 and 9.8 × 104 conidia ml-1) values in adult insects. In nymphs, M. anisopliae CPD 5 was the most …

Cleome Hirta Essential Oil As Livestock Tick (Rhipicephalus Appendiculatus) And Maize Weevil (Sitophilus Zeamais) Repellent, M. W. Ndungu, S. C. Chhabra, W. Lwande

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The repellency of the essential oil of the shrub Cleome hirta and of three identified constituents (phytol, (+)-cedrol, n-octacosane) was evaluated against the livestock tick, Rhipicephalus appendiculatus and the maize weevil, Sitophillus zeamais. In a tick climbing repellency bioassay, the oil exhibited repellency which, at the highest dose, was comparable to that of the commercial arthropod repellent N,N-diethyltoluamide (DEET). In a Y-tube olfactometer bioassay, the oil showed higher or comparable repellency against S. zeamais relative to DEET at all the doses tested. The potential of C. hirta in livestock tick and maize weevil control is discussed. Copyright (C) 1999 Elsevier …

Potential Of The Entomopathogenic Fungus, Metarhizium Anisopliae (Metsch.) Sorokin For Control Of The Legume Flower Thrips, Megalurothrips Sjostedti (Trybom) On Cowpea In Kenya, S. Ekesi, N. K. Maniania, K. Ampong-Nyarko, I. Onu

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Field experiments were conducted at Mbita, western Kenya for two seasons to evaluate the potential of the entomopathogenic fungus, Metarhizium anisopliae (Metsh.) Sorokin, for biological control of the legume flower thrips, Megalurothrips sjostedti (Trybom), on cowpea. An ultra-low-volume (ULV) oil/aqueous formulation and a high-volume (HV) aqueous formulation of conidia were applied three times each at two concentrations of 1 x 1011 and 1 x 1013 conidia ha-1. Compared with the untreated controls, both formulations significantly reduced thrips populations and plant damage in both seasons. Adult insects collected from fungal-treated plots and reared in the laboratory showed a high mortality due …