In vitro inhibition of tomato Fusarium wilt causative agent by zearalenone from a soil inhabiting fungus

To find naturally occurring compounds for the control of Fusarium wilt disease of tomato in the farming fields, 200 fungal strains were cultured in liquid media and screened for antifungal activity against Fusarium oxysporium f. sp. Lycosperci. The screening was carried out using in vitro antifungal assays and coincidentally a strain of Fusarium species was found to produce secondary metabolites, which were prepared as crude extracts that showed strong antifungal activity. The responsible compound was purified using column chromatography and the chemical structure of the purified compound was determined using nuclear magnetic resonance (NMR) spectroscopic techniques. A known compound, zearalenone, was found to be responsible for the antifungal activity, with a minimum inhibitory concentration (MIC) of 550 ± 10.5 ppm. This is a sufficient inhibition for F. oxysporium f. sp. Lycosperci, which is the causative agent for Fusarium wilt disease to tomato. Given the global abundance of zearalenone and its implication to human health, the results from this study suggest a sustainable manner of disposing of the mycotoxin and simultaneous benefit in control of the Fusarium wilt disease. It is recommended from this finding that it can be used to suppress fungal attack onto the roots of tomato plant to manage the Fusarium wilt disease.Keywords: Fusarium oxysporium f. sp. Lycosperci, tomato, submerged cultures, column chromatography, zearalenon

Improving the Cost-Effectiveness of Artificial Visual Baits for Controlling the Tsetse Fly Glossina fuscipes fuscipes

Tsetse flies, which transmit sleeping sickness to humans and nagana to cattle, are commonly controlled by stationary artificial baits consisting of traps or insecticide-treated screens known as targets. In Kenya the use of electrocuting sampling devices showed that the numbers of Glossina fuscipes fuscipes (Newstead) visiting a biconical trap were nearly double those visiting a black target of 100 cm×100 cm. However, only 40% of the males and 21% of the females entered the trap, whereas 71% and 34%, respectively, alighted on the target. The greater number visiting the trap appeared to be due to its being largely blue, rather than being three-dimensional or raised above the ground. Through a series of variations of target design we show that a blue-and-black panel of cloth (0.06 m2) flanked by a panel (0.06 m2) of fine black netting, placed at ground level, would be about ten times more cost-effective than traps or large targets in control campaigns. This finding has important implications for controlling all subspecies of G. fuscipes, which are currently responsible for more than 90% of sleeping sickness cases