Background:The thread caterpillar Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), is an insect pest that attacks the lettuce, Lactuca sativa and this is a serious problem faced by farmers in Niassa province due to the fact that at the end of the fourth larval stage it (insect) cuts saplings and compromising agricultural output. Usually the control of this pest has been done using synthetic insecticides, but these have environmental related implications. Thus the researches of eco-friendly forms of control have been studied. Methods:In this research, the lettuce intercropping with onion Allium cepa was carried out to control the insect pest A. ípsilon. The experiment took place at the Agricultural Research Institute of Mozambique-IIAM. Several trials, one in monoculture (only lettuce) and other intercropped with onion were performed. In the experiment different intercropping patterns were tested, namely: Surround (a continuous line of onion surrounding a lettuce line), alternating (a line of onion and another of lettuce) and two lines of lettuce and one of lettuce.Results: Based on tests conducted, the intercropping of lettuce with onion resulted in more plant not attacked after the test compared to the monocrop (only lettuce). In the same research we studied the best pattern to intercropping and it was found that the surrounding form (a continuous line of onion encircling a lettuce line), after the experiment, showed a higher average number of non-attacked lettuce plants. Conclusions:Surrounding was the best intercropping pattern because showed a higher average number of nonattacked lettuce plants. The current results indicate that the onion can be used as useful tool to control the caterpillar, A. ipsolon in lettuce.

Solar water disinfection (SODIS) is an effective and inexpensive microbiological water treatment technique, applicable to communities lacking access to safely managed drinking water services, however, the lower volume of treated water per day (< 2.5 L per batch) is a limitation for the conventional SODIS process. To overcome this limitation, a continuous-flow solar water disinfection system was developed and tested for inactivation of Acanthamoeba castellanii cysts and Escherichia coli, Salmonella Typhimurium, Enterococcus faecalis, and Pseudomonas aeruginosa. The system consisted of a solar heater composed of a cylindrical-parabolic concentrator and a UV irradiator formed by a fresnel-type flat concentrator combined with a cylindrical-parabolic concentrator. Deionized water with low or high turbidity (< 1 or 50 nephelometric turbidity unit (NTU) where previously contaminated by 10 8 Cysts/L or 10 5 -10 6 CFU/mL of each of four bacterial species. Then was pumped from the heating tank flowing through the heater and through the UV irradiator, then returning to the heating tank, until reaching 45, 55, 60 or 70 °C. The water was kept at the desired temperature, flowing through the UV irradiator for 0.5 and 10 min. Trophozoites were not recovered from cysts (during 20 days of incubation) when water with < 1 NTU was exposed to UV and 60 °C for 0.5 min. In water with 50 NTU, the same result was obtained after 10 min. In water with < 1 NTU, the inactivation of all bacteria was achieved when the water with < 1 NTU was exposed to 55 °C and UV for 0.5 min; in water, with 50 NTU the same result was achieved by exposure to 60 °C and UV for 0.5 min. The prototype processes 1 L of water every 90s. The system is effective and has the potential to be applied as an alternative to the large-scale public drinking water supply.

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