In the search for alternatives to sawdust as growing media in commercial mushroom cultivation, three organic substrates obtainable as crop residue, maize husk, maize cob, and maize stalk, with each being supplemented with rice bran, were evaluated as growth media for the oyster mushroom, Pleurotus ostreatus (Kummer). For the tested alternatives to sawdust, the harvested weight of fruiting bodies that sprouted on a kilogram maize husk media per crop (32.99 g) was the highest. Sawdust media supported significantly ( < 0.001) heavier fruiting bodies (42.18) than the maize residues. The peak mushroom harvests for the various substrates were obtained between the first and seventh fruiting body flushes. The biological efficiency of the substrates, which measured usable nutrients indicated that maize stalk supplemented with rice bran, was 39% compared to that of the sawdust media (60%). The maize husk media and the maize cob media had biological efficiencies of 32% and 9.5%, respectively. These results indicate that two of the tested growing media (maize stalk or husk) produced mushrooms with yield characteristics that were comparable to the well-used sawdust in the cultivation of oyster mushrooms. The environmental and economic parameters involved in the use and carting of sawdust make these on-farm crop residues a viable alternative for mushroom cultivation in especially nonforest zones of Ghana.

Sesame is an oilseed crop which can be grown on marginal lands. Selection of stable sesame cultivars that can adapt to local environmental conditions can be a very important food security strategy. A set of 21 high yielding sesame accessions that have been selected for a temperate region were grown in the transitional zone of Ghana during the major season of 2014. The seeds were sown after the first rain in the year in a completely randomized design, with three replications. The objective was to evaluate the effect of the contrasting environment on sesame phenology and to select cultivars with yield potential that can be accepted into local farming systems in the new environment. Morphological, physiological and agronomic traits, leading to yield were recorded in this study. Number of capsules per plant had the strongest association (72%) with seed yield. Five accessions showed a combination of early maturity < 12 weeks with high overall mean seed yield (> 20 g per plant) and good harvest index (0.29). Based on their mean performance these cultivars have been selected as promising exotic cultivars for the new locality.

Three diverse insects, a polyphagous "leaf chewer" (Atractomorpha lata), a polyphagous "sap feeder" (Myzus persicae), and a "restrictive feeder" (Plutella xylostella) responded differently when fed with eight cultivars of sesame either as whole leaf or via artificial diet. There was limited or no correlation in induction between detoxifying enzyme substrates (esterase, glutathione s-transferase [GST], and mixed function oxidase [MFO] activities) when activity toward various substrates α-naphthyl acetate, 1-chloro-2,4-dinitrobenzene, 1,2-dichloro-4-nitrobenzene, and p-nitroanisole (pNA), were compared although they were generally elevated in the tissues from insects on sesame than a reference fed with radish seedlings. In A. lata, esterase activity for the cultivar 11Pusan and 45Laos were three-fold higher compared to the reference, while other cultivars, 24Nanbu-twasaki and 56S-radiatum were--two- to three-fold lower than the reference. In M. persicae, the esterase activity was as much as five-fold higher than the reference in one test cultivar. GST activities of the sesame cultivars were generally higher (≈two-fold) than the reference in all insects and at variable ratios among the cultivars. The MFO activity toward pNA in grasshoppers feeding on these sesame cultivars was either highly expressed or nonexistent. These results indicate that although the cultivars belong to the same species, they might have undergone changes in secondary phytochemicals in response to varying biogeographical distribution. Each insect species is suspected to target a specific plant chemical burden that it tries to overcome in each cultivar through enzyme activation.

Abstract:The diamondback moth, Plutella xylostella L., has developed resistance to most insecticides used for its management. Suggested alternatives to forestall this process include biorational insecticides in mixtures with low-risk insecticides. The aim of this study was to select an insecticide or insecticide mixture that could be adopted by small-scale growers for diamondback moth management. The effectiveness of four insecticide mixtures, i.e., Agroneem ® Plus (neem-derived), Spinosad (microbial origin), thiamethoxam (neonicotinoid) and a homemade methanol Jalapeño pepper extract, in laboratory bioassays was evaluated. Binary mixtures were tested against single products at manufacturer's label rates. These were applied to collard greens using the leaf dip method and fed to the newly molted 2nd or 3rd instar larvae. Mixtures were evaluated for efficacy based on larval mortality and consumption of leaf discs. The results showed interactions between Jalapeño pepper extract and Spinosad and between the neem-derived Agroneem ® Plus and thiamethoxam at some of the tested concentrations. Mixtures with at any amount of Spinosad killed all larvae. The neem-based product gave inconsistent results in some treatments; in some case, increased leaf damage did not result in commensurate larval mortalities. The reported resistance of diamondback moth larvae to Spinosad was not observed during this study, neither with Spinosad alone nor in mixtures.