Trend in Mango Production and Potential Threat from Emerging White Mango Scale, Aulacaspis tubercularis (Homoptera: Diaspididae) in Central and Eastern Kenya

White mango scale, Aulacaspis tubercularis Newstead was reported to have been recorded in Kenya long ago. However, there has been no documented report of study regarding its impact on mango production in this country. The current study surveyed the distribution, severity status, farmer's knowledge and management practices of A. tubercularis in three counties in central and eastern Kenya in 2015. It was found that the pest was distributed in almost all of the 75 orchards addressed in the counties. The mean and standard deviation of female A. tubercularis on mango leaf was 1.35+.81 in Kiambu, 2.75+3.17 in Machakos and 1.47+1.49 in Murang’a County, indicating irregular distribution among orchards of each county, mainly among that of Machakos and Murang’a. The severity status was found to have been more of mild with few high and very high statuses. About 66.67% of mango growers knew the presence of the insect of which 14% did not consider it as pest. About 57.33% of the respondents attempted to control white mango scale by the use of pesticides and other methods, of which 13.95% said, could control it as planned. Further systematic study is needed to implement informed management system to control this emerging mango pest. Keywords: White Mango scale, severity, control, frui

Tomato Production Characteristics, Biotic Constraints and their Management Practices by Farmers in Bungoma County, Kenya

Tomato (Solanum lycopersicum L.) is an important crop in Bungoma County, Kenya. Its production is constrained by arthropod pests and diseases which make farmers rely heavily on synthetic chemicals to control them. To support the development of effective integrated pest and disease management strategies on tomato, a survey was carried out in Sirisia, Bumula and Mt. Elgon sub-counties. A total of 90 randomly selected farmers in the region were interviewed using a structured questionnaire. Data collected included demographic characteristics of farmers, tomato varieties, farm size, prevalence of pests, diseases and their management practices. Majority of the respondents were male with 89.7% in Mt. Elgon. Most of the respondents had primary education. The varieties of tomato grown were Rio-grande, Kilele, Carl-J, Money-maker, Safari and Onyx. The average farm size ranged from 0.25 to 1.0 hectare with 80.4% in Sirisia. Most prevalent pests affecting tomato were Frankliniella occidentalis (58.6%) and Bemisia tabaci (35%) while the most reported disease was Ralstonia solanacearum (75%). The chemicals used against pests included Imidacloprid (24.4%), Alpha-Cypermethrin (20.7%) and Lambda-cyhalothrin (20%). Farmers controlled diseases using Metalaxyl-M, Mancozeb, Propineb and Carbendazim. Out of the total ninety respondents in the region, only 2.4% in Sirisia used bio-pesticides. At least 60%, 22% and 20.7% of respondents in Bumula, Sirisia and Mt. Elgon, respectively used more than one chemical. About 10% of respondents in Bumula and 6.9% in Mt. Elgon applied chemicals twice a week. In Sirisia, about 53.6% reported that the chemicals used effectively controlled the pests and diseases compared to Bumula (61%) and Mt. Elgon (58.6%) who reported that they were ineffective. The main source of advice on crop protection was Agrovet shops. The findings revealed that pest and diseases limited tomato production in the region. The study therefore recommends increased awareness on proper use of chemicals and use of safer alternatives such as bio-pesticides to reduce on pesticide residues and the production cost. Future studies on the level of synthetic chemical residues in tomatoes produced in the region should be conducted. Keywords: Bio-pesticides, chemicals, diseases, pests, tomato. DOI: 10.7176/JNSR/9-12-07 Publication date:June 30th 201

Diversity, distribution and role of wild crucifers in major cabbage and kale growing areas of Kenya

An investigation of the diversity and distribution of wild crucifer species and their importance for cultivated crucifers was conducted during 2005 and 2006 in the highland and mid-altitude semi-arid areas of Kenya. Thirteen species of wild crucifers in nine genera were recorded: Raphanus raphanistrum, Erucastrum arabicum, Sisymbrium officinale, Crambe kilimandscharica, Capsella bursa-pastoris, Rorippa nudiuscula, Ro. micrantha, Ro. microphylla, Lepidium bonariense, Coronopus didymus, Brassica rapa, B. juncea and an unidentified Brassica species. Highland areas had significantly higher species diversity and species richness than mid-altitude semi-arid areas. Species richness, diversity and evenness varied with season and location. Raphanus raphanistrum was the dominant non-cultivated species in the highlands followed by E. arabicum, which was also present and dominant in the semi-arid study sites. Diamondback moth (DBM) was recorded from ten wild crucifer species and R. raphanistrum and E. arabicum were the preferred host plant species. Overall, four larval, one larval-pupal and one pupal parasitoid of DBM were recorded: Diadegma semiclausum, D. mollipla, Apanteles sp., Cotesia plutellae, Oomyzus sokolowskii and Brachymeria species, respectively. Diadegma semiclausum was the most dominant species on all crucifers. We conclude that wild crucifers act as alternative hosts for DBM and provide refugia for DBM parasitoids, which risk local extinction through pesticide application or competition from introduced exotic parasitoid species. The wild crucifers also act as recolonization sites for DBM parasitoids

Oviposição do curuquerê e alimentação de suas lagartas neonatas em algodoeiros tratados com caulim

Resumo: O objetivo deste trabalho foi avaliar a capacidade do caulim de afetar a oviposição e a alimentação de Alabama argillacea (Lepidoptera: Noctuidae) em algodoeiro. Determinou-se a preferência de oviposição, a viabilidade de ovos e o consumo das lagartas de primeiro instar de A. argillacea, em folhas de algodão tratadas ou não com caulim. A preferência de oviposição foi determinada por teste de escolha e confinamento, em delineamento experimental de blocos ao acaso, em arranjo fatorial 2x7, representado pelos tratamentos com caulim em água destilada (60 g L-1) ou somente água destilada (testemunha), e pela avaliação de sete estruturas vegetais da planta. O consumo pelas lagartas de primeiro instar foi determinado em delineamento experimental inteiramente casualizado, em arranjo fatorial 2x4, representado pelo tratamento com caulim em água destilada, pela testemunha e pelos quatro períodos de observação (6, 12, 24 e 48 horas). A oviposição das mariposas do curuquerê-do-algodoeiro foi reduzida nas plantas de algodão tratadas com caulim; no entanto, a viabilidade dos ovos não foi afetada. A folha da haste foi a estrutura preferida para oviposição. A sobrevivência e o consumo de lagartas de primeiro instar do curuquerê são menores nas plantas de algodão tratadas com caulim

Trends and emerging drugs in Kenya: A case study in Mombasa and Nairobi County

Background: Increasing popularity of emerging drugs or the ‘legal high’ is of major concern to the Government. Emerging psychoactive substances e.g. morphine, carnabinoids, cathinones are not controlled and are believed to cause harm if not more than controlled drugs. They are being sold all over as legal substances and consumed openly.Objective: To evaluate the trends and patterns of emerging drugs use, magnitude and their impact in the Counties.Methods: A questionnaire was administered to 702 respondents in Nairobi and Mombasa Counties. The social dynamics, types of emerging drugs, drug initiation age, source of drugs, venue of consumption, and their effects on respondents among other issues were investigated. Qualitative, univariate and multivariate logistic regression analyses were done.Results: The drug initiation age ranged from 5 to 28 years though most started abusing the drugs at 21years (18%), with over 81% being introduced by friends. They are abused for their stimulating, hallucinating, depressants effects on the streets, club, drug dens, party but rarely at home and schools. Forty one (41) emerging drugs (see text) comprising of one or combinations of drugs were recorded, with Nairobi recording significant higher number of emerging drugs than Mombasa. Most of the highly abused drugs were ‘kuber, shisha, shashaman, mau, tambuu, jet fuel, kukumanga, mkorogo, mshomoro, rohypnol, Artaine and kamusi. ‘Shisha’ and ‘kuber’ were most commonly abused drugs in both counties. Over 25% of the shisha and kuber abusers aged between 26 to 35 years. The emerging drugs were purchased drugs from various outlets, thus making it difficult to track. Some respondents injected either heroin or cocaine while others injected both heroin and cocaine thus, placing the individuals at risk of contracting Human Immunodeficiency Virus (HIV) and Hepatitis C. The emerging drugs have a lot of impact on the county’s security, economy, education, school drop-out rate, non performance at work place and reproductive health.Conclusion and recommendations: The Government should set up of rehabilitation centres, training programmes on alcohol and drug abuse, establish Employee Assistant Programmes, wellness centres, control sale  of prescription medicine, stiff penalties on drug peddlers and ban of advertisement on media. There is need for all stakeholders to review the alcohol and Drug Abuse policy to include new and emerging drugs in order to mitigate illnesses deaths and associated with emerging drugs. Government should come up with ways of tracking and controlling the emerging drugs especially shisha, kuber, and prescription medicine. Alcohol and Drug Abuse (ADA) issues should be incorporated in the education curriculum at all levels.Key words: Emerging drugs, shisha, kuber, causes, mitigations, combinations, administratio

Screening for resistance against major lepidopteran and stem weevil pests of amaranth in Tanzania

Published online: 25 Sept 2018Insect pests pose major challenges to optimum productivity of amaranth in Africa and Asia. The use of insecticides is the main control strategy, but is expensive and may pose health and environmental concerns, especially if proper care is not taken. Host plant resistance offers a cheap and sustainable pest management alternative. Open field experiments were conducted during two cropping seasons in 2016 and 2017 to screen 35 amaranth accessions and lines for resistance to leaf-webbers and stem weevils. The diversity (H) of lepidopteran defoliators and their parasitoids on each accession ranged from 0.00 to 1.57 and 0.00 to 1.65, respectively during the long rainy season and from 0.00 to 1.58 and 0.00 to 1.01 in the short rainy season. Accessions VI036227, RVI00027, VI054569, VI033487, VI044432, VI048076, VI049639, VI049530 and VI049698 had high levels of pest resistance with significantly lower infestations (≤ 11.11 ± 2.14%) and damage (≤ 68.06 ± 3.90%) by leaf-webbers and leaf-worms. Stem weevil infestations ranged from 68.70 ± 2.0% to 90.42 ± 1.0% during the long and short rainy seasons, respectively. Accessions VI047517-B, VI036227 and VI056563 had the least stem weevil infestations (< 62.5%) but differences among accessions for damage incidences were non-significant. Parasitism was observed in all the accessions except seven of them. Amaranth accessions exhibiting pest resistance or at least non-preference traits are important for success of breeding programs. The importance of deploying such accessions to breed for improvement of susceptible lines (by introgression) or their release to farmers, if they have desirable horticultural traits that are required by vegetable producers and consumers, for effective management of amaranth pests is also discussed

The effects of pest-resistant amaranth accessions on the performance of the solitary Endoparasitoid apanteles hemara (Hymenoptera: braconidae) against the amaranth leaf-webber Spoladea recurvalis (Lepidoptera: crambidae)

The leaf-webber Spoladea recurvalis F. is the most devastating pest of amaranths in East Africa. Recent collaborative research in Asia and East Africa revealed one highly resistant amaranth accession (VI036227) to the pest and seven moderately resistant ones (RVI00053, VI033479, VI044437-A, VI047555-B, VI048076, VI049698, and VI056563). The solitary koinobiontic endoparasitoid Apanteles hemara Nixon has also been reported as efficient against the pest. Plant resistance to herbivores may have bottom-up effects on their parasitoids. In this study, we assessed the effects of the seven moderately resistant amaranth accessions and one susceptible accession (VI033482) on the performance of A. hemara. Except VI056563 that recorded lower parasitism rates compared to the susceptible accession, A. hemara performed well on all the other moderately resistant accessions. The longevity of the parasitoid was significantly extended on the resistant accessions compared to the susceptible one. While the parasitoid’s body size, developmental time, and survival differed significantly between resistant accessions, they were similar to results obtained on the susceptible accession. Furthermore, while the parasitoid’s sex ratio was male-biased in the susceptible accession, balanced sex ratios were obtained from accessions RVI00053, VI033479, VI044437-A, VI047555-B, VI048076, and VI049698. Significant nonreproductive host larval mortality was induced by A. hemara on all the tested accessions. These results suggest that the moderately resistant accessions can be used in combination with the endoparasitoid A. hemara to manage S. recurvalis and other amaranth leaf-webbers in the context of integrated pest management

Effects of host age and density on the performance of Apanteles hemara (Hymenoptera: Braconidae), a larval endoparasitoid of Spoladea recurvalis (Lepidoptera: Crambidae)

The amaranth leaf-webber, Spoladea recurvalis (Fabricius; Lepidoptera: Crambidae), is a serious pest of Amaranthus sp. in Africa and Asia. Apanteles hemara (Nixon; Hymenoptera: Braconidae) is by far the most important larval endoparasitoid of the amaranth leaf-webber. We examined the effects of host density and age on the biological characteristics of A. hemara. The regression model of the number of hosts supplied to A. hemara against the number of larvae parasitized resulted in a curve corresponding to type II functional response, with a significant increase in the number of hosts parasitized up to the density of 30 hosts before being constant up to 40 hosts. In contrast, the parasitism rate decreased linearly with increasing host densities. Development time, sex ratio, and adult longevity were not significantly affected by host density. The immature parasitoid mortality was significantly higher at higher host densities. Apanteles hemara did not parasitize 7-d-old larvae and beyond, while parasitism was significantly higher among 1- to 2-d-old compared with 3- to 4-d-old larvae. Immature parasitoid mortality was 2.6 times higher in 1- to 2-d-old larvae compared with 5- to 6-d-old larvae. The developmental period of the parasitoid from egg to adult was longest among 1- to 2-d-old larvae and least among 5- to 6-d-old larvae. Nonreproductive mortality was markedly higher among 1- to 2-d-old larvae compared with the older larvae. Adult female A. hemara were significantly larger on 3- to 4-d-old larvae compared with either 1- to 2-d-old or 5- to 6-d-old larvae. We discuss the implications of our results for the interpretation of functional response in parasitoids, mass rearing, conservation, and augmentative biological control of S. recurvalis