Non-target aquatic organisms such as fish may be impacted by agricultural activities through the runoff of pesticides from farms into aquatic ecosystems. In this study, the genotoxic (erythrocytic micronuclei) and histological effects of sublethal concentrations (1% and 10% of 96-h median lethal concentration (LC50) values) of two pesticides (dichlorvos and paraquat) were evaluated in Clarias gariepinus (the African Sharptooth Catfish) for 28 days. The 96-h LC50 of dichlorvos and paraquat against fingerlings of C. gariepinus was 730 µg/L and 50 µg/L, respectively. There was a significant dose-dependent increase (p<0.05) in micronuclei in the erythrocytes of exposed C. gariepinus (2.00±0.82 ‰ to 3.25±1.26 ‰ for dichlorvos and 2.25±0.96 ‰ to 4.75±0.96 ‰ for paraquat) compared to control (0.75±0.96 ‰) by day 28. Gill histological alterations such as mild to severe necrosis and blunting of secondary lamellae were observed in C. gariepinus exposed to higher sublethal concentrations of both pesticides. This study showed that non-target aquatic organisms like C. gariepinus may be at risk of adverse biological effects from exposure to pesticides from non-point sources. We recommend environmental monitoring and sensitization on responsible pesticide use to stakeholders. This will forestall potential adverse ecological effects in aquatic ecosystems.

Populations of the cocoa mirid, Sahlbergella singularis Haglund (Hemiptera: Miridae), on cocoa, Theobroma cacao L. (Malvaceae), display sharp seasonal fluctuations in population size. To better understand factors and mechanisms involved in seasonal variation, we studied the life history traits of 10 successive generations of a caged population under field conditions. Nymphal survival and development were assessed on pods stored under cocoa canopy, whereas female survival and fecundity were evaluated on sleeved pods in cocoa trees. At the same time, cocoa phenology and cocoa canopy microclimate were characterized. A life table analysis was conducted with survival and fecundity temporal data. Reproductive parameters showed far more variation than nymphal development parameters, both within and among generations. We obtained low intrinsic rates of natural increase (about 0.04), the variation of which was mainly linked to the decrease in fecundity. Fecundity as well as life table parameters varied in accordance with natural population fluctuations, suggesting that S. singularis seasonal variation might be mainly linked to variation in female fecundity. A multiple regression analysis showed that variation in female fecundity was first correlated with the presence of young fruits on cocoa trees. Fecundity was also weakly affected by daily minimum r.h. and daily mean temperature. The usefulness of our results for modeling of S. singularis population dynamics and for the improvement of IPM strategies is discussed.

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The brown cocoa mirid,Sahlbergella singularisis the most important insect pest of cocoa for field damage has been classified into three categories that include blast, stagheadedness and mirid pocket. The mirid attack predisposes the cocoa plant to secondary infection by opportunistic pathogenic fungi. This study evaluated the dieback conditions associated with mirid damage due to associated fungi from lesions on pods, twigs and pin punctures. The relationship betweenPhytophthorablack pod infection and mirid infestation in the field was also established. The results indicated that dieback progression from the mirid lesions (8.5 mm) was significantly different (P&lt; 0.05) from that of pin punctures (7.8 mm).Lasiodiplodia theobromaehad the highest proportion of isolates from pods (33%), twigs (47%), and pin punctures (38%).Fusarium decemcellulare(Albonectria rigidiuscula) accounted for 27.8% and 31.6% from pods and twigs; however, it was not recovered from pin punctures. Other isolated pathogens wereAspergillusspecies andRhizoctoniaspecies. There was a significantly strong positive correlation coefficient of 0.74 between the mirid population and the black pod disease infection in the field. The major fruit-bearing season of cocoa witnessed an increase in mirid infestation and blackpod infection. The effect of mirid–pathogenic fungi-associated damage could be ameliorated through effective crop husbandry practices to ensure that cocoa plant tissues are not unduly exposed to biological and mechanical injuries.

Indoxacarb gel bait was evaluated for its efficacy in the laboratory and field against American cockroaches, Periplaneta americana (L.), and German cockroaches, Blattella germanica (L.). Advion 0.6% indoxacarb gel bait was toxic to both P. americana and B. germanica. There were no significant differences in the LT50 (h) values for treatment levels of 0.25 g, 0.5 g, and 1.0 g gel applied against P. americana, whereas gel applied at 0.5 g to B. germanica had a significantly greater LT50 (h) in the laboratory than the gel treatments on P. americana. The LT50 for both cockroach species ranged from 40.65 to 145.60 h. There was no control mortality in the laboratory bioassays. In the field, 55 houses were treated with 0.5 g of 6-8 spots of indoxacarb gel bait per kitchen of two or three bedroom bungalows from three Local Government Areas of Lagos State, comprising Surulere (22), Alimosho (12), and Shomolu (21). Mean reduction in cockroach populations varied from location to location based on the level of infestations. Percentage reductions in the indoxacarb gel-treated units ranged from 3.5% at 1 d after treatment to 99.8% at 14 d at Surulere, while reductions ranged from 8.9% at 1 d after treatment to 99.7% at 14 d at Shomolu; a similar trend was observed for Alimosho. Indoxacarb gel bait was highly effective in the control of cockroaches.

The brown cocoa mirid, Sahlbergella singularis Haglund has been adjudged the most economically important insect pest of cocoa across West African the sub-region. The pest is capable of causing yield loss of about 30% in the first cocoa growing season and up to 70% yield loss in not less than two cocoa seasons if not controlled. This paper presents the population dynamics of S. singularis in Ibadan, Nigeria and the interactions between field populations of mirids and density dependent (natural enemies) and density independent (weather parameters) factors. One hundred mature cocoa trees were randomly sampled from base to 1.5m Girth at Breast Height (GBH) fortnightly on a two hectare plantation for adult S. singularis and its natural enemies (Camponotus species, Crematogaster brevispinosa, Oncophylla longinoda, Acantholepis capensis and Palothyreus tarsatus) using standard procedures. Mirid population and natural enemy abundance were correlated to monthly weather parameters (Temperature, Relative humidity and Rainfall). The population dynamics followed a similar trend over a period of three years of study. The population of the pest rapidly built-up in August of each month and this coincided with the period of the main cropping season of cocoa, as cocoa trees were in massive pod production. Weather parameters such as temperature and relative humidity played a major role in the fluctuations of mirid population. Rainfall did not seem to have any impact on the pest dynamics. Peak relative humidity data of 88.2%, 84% and 83.5% were recorded in August 2004August , 2005August and 2006, respectively and the temperature readings declined around this period, inadvertently favouring the multiplication of mirid numbers in the field. The roles of density-dependent factors, that is, natural enemies, were observed in the field and reported. Ants of various genera were observed to exert different degrees of predation in the field, however, there were no parasitoids encountered both in the field and laboratory throughout the period of this study. Knowledge of the seasonal abundance of the pest is important to generate enough background information needed for effective control of mirid in Nigeria.

This study focused on the management of established Apis mellifera adansonii colonies, and evaluation of the proximate, mineral, and pollen contents of honeys produced by these bees at the University of Lagos apiary. Two newly established bee colonies were managed using modern hive management techniques. Honeys produced by these colonies were subjected to further laboratory analyses. Proximate composition of honey samples was determined based on the official analysis methods from Association of Official Analytical Chemists (AOAC). Mineral composition was determined quantitatively using atomic absorption spectroscopy (AAS). Melissopalynological analysis was conducted to ascertain the amount, type and origin of pollen present in the samples. On the basis of the proximate composition, colony 1 honey had higher carbohydrate (81.29%), crude fibre (1.43%) and ash contents (0.70%) while colony 2 honey recorded higher protein (2.72%), crude fat (0.17%), moisture content (17.32%) and pH (4.6). Result of the mineral analysis showed that potassium was the most abundant element, while manganese was the least present trace element in both honeys. Investigated honey samples contained 8609 pollen and spore types belonging to 27 families and 29 species. Colony 1 honey had the highest pollen diversity, while colony 2 honey recorded the highest abundance. Hippocratea sp. was the predominant pollen type in colony 1 honey sample while Phyllantus sp. was the secondary dominant species in colony 2 honey. Celastraceae and Rubiaceae were the most dominant families recorded in the investigated honey samples. Investigated honey samples were multifloral, rich in minerals, and met the standard requirements of good honey as recommended by International Honey Commission. The study provided the basis for identification of major plants visited by Apis mellifera honeybees within the apiary. There is a need to conserve the existing flora within the study location, especially those found to be rewarding to Apis mellifera adansonii.