Evaluation of soil solarisation as a tool for Integrated Pest Management (IPM) in small tobacco farms in southern Brazil
Soil solarisation has a successful history as an environmentally friendly tool for IPM using solar power to control a range of soilborn plant pathogens. Therefore, this technique was evaluated in tobacco production areas in southern Brazil as a complementary practice to pest control in order to better support the sustainability of tobacco production on small farms. Seven distinct small farms with historical tobacco production were selected for this trial. Each area comprised two macro plots (8.4 × 25 meters) with treated (solarised) and untreated areas. All macro plots were uniformly prepared, over irrigated and treated ones covered with a transparent plastic sheet. Probes were installed in all plots to measure the temperature at 10 cm depth (data points collected every hour) during 46 days. Soil samples (7 per plot; treated and untreated) were collected just before and after treatment for analysis of microorganisms, nematodes, insect larvae and weed control. These plots were under crop rotation with black oat, where tobacco plants will be cultivated (200 plants per plot; 4 rows of 50 plants). These plots will be evaluated for pest incidence, yield and quality. All treated plots recorded a minimum of 577 hours above 40 °C at 10 cm depth. This solarisation treatment was effective in reducing Ralstonia solanacearum (all plots) and Fusarium sp (majority of plots) populations. This technique was also efficient for nematode populations reduction (Helicotylenchus sp, Meloidogyne sp and Pratylencus sp). Insect larvae were not observed in these experimental areas. Weeds were not observed in treated plots (100 % control), except for Cyperus rotundus. All results summarised above suggest that solarisation is a potential IPM tool to pest control in tobacco production areas in southern Brazil. The technique could be used as a complementary support towards sustainable production on small tobacco farms.