Integrated impact of soil solarization and organic mulching on insects, weeds, and plant performance

Soil solarization is a hydrothermal method for managing soil-borne plant insects, weeds, nematodes, and fungi. Mulching is a method to control weeds along with providing shelter for predatory insects. The integrated impact of soil solarization and mulching on weeds, nematodes, insect pests and plant performance was evaluated in field grown ‘Potomac Pink’ snapdragon (Antirrhinum majus L.) in fall 2008 at University of Florida Plant Science Research and Education Unit, Citra, FL. Four treatments, solarization (S), mulch (M), integration of mulch and solarization (MS), and an untreated control (C), were arranged in a randomized complete block design with five replications. In mulch treatment, a pre-plant mulch of sunn hemp (Crotalaria juncea L.) hay was applied over the bed surface. In solarization treatment, beds were covered with Polydak plastic film for 6 weeks, after which they were planted with snapdragons after removing the plastic. In MS treatment, plastic was applied as pre-plant, and sunn hemp mulch as post-plant application. Data was collected on snapdragon mortality, weed ratings, plant weight and number of blooms, and visual count of insects, especially buckeye caterpillar (Junonia coenia Hübner, Lepidoptera: Nymphalidae) and saltmarsh caterpillar (Estigmene acrea (Drury), Lepidoptera: Arctiidae). Solarization or mulching alone reduced weed numbers but integration of solarization and mulching provided the most effective control of weeds. Number of large buckeye caterpillars was highest in the MS treatment. Plant mortality and plant parameters did not differ among the treatments. Extensive plant damage and mortality due to caterpillars were observed in all plots.