Effect of bioslurry-enriched vermicomposts on twospotted spider mite (tetranychus urticae koch), yield and postharvest quality of statice (limoniun sinuatum mill).

Abstract

Statice (Limonium sinuatum Mill) is an outdoor flower providing potential for expansion and product diversification in floriculture. Its production is constrained by rising cost of inputs, declining soil fertility and pest damage. The twospotted spider mite is a major pest causing yield losses. Inorganic fertilizers and synthetic miticides are expensive and cause pollution. This study sought to determine effects of bioslurry and vermicomposts as fertilizers on yields and quality of statice, and on TSSM. The study was conducted at Egerton University in Njoro, Kenya, using a 2×4 factorial experiment laid out in a RCBD in the field and CRD in the laboratory. The three vermicompost treatments were Kitchen waste (V1), mowed lawn grass (V2) and Weed biomass (V3), all applied at a rate of 40% by volume mixed with garden soil, and compared with the control (V0). Bioslurry was applied at 7.8 tons/ha (B1), and compared with the control (B0). Results showed significant main and combined treatment effects on parameters at P≤0.05, when compared with the control. Statice inflorescences from plants treated to the organic fertilizers, singly or in combination, had significantly fewer TSSM (ranging from 5.2 to 10.4 mites) indicating greater mite repellence, when compared with the control (11.2 mites). The biofertilizers, also had significant main and combined effect on growth and yield parameters, when compared with the control. They resulted in significant increased number of days to flowering (ranging from 17.3 to 26.9 days), compared to the control (12.3 days), increased number of stems per plant (ranging from 26.2 to 32.5 stems) compared to the control (22.1 stems), increased stem length at 60 days after transplanting (ranging from 77.0 cm to 112.6 cm) compared to the control (40.1 cm), and increased fresh weight of flower stems (ranging from 20.0g to 31.6g) compared to the control (12.4 g). The organic fertilizers also resulted in significant main and combined effect on statice postharvest quality parameters. When compared to the control, they resulted in significantly enhanced water uptake during days in the vase (DIV), throughout the observation period. The observed water uptake was significantly higher at 3 DIV (ranging from 52.8 to 70.8 ml), and was still much higher at 15 DIV (ranging from 34.7 ml to 50.8 ml) compared to the control (48.1 ml and 3.3 ml respectively at 3 DIV and 15 DIV). Application of the manures significantly increase vase life of statice (ranging from 15.8 days to 22.5 days) compared to the control (11.7 days). It is therefore concluded that the treatments have significant favourable effect on TSSM repellence, growth, yield and postharvest quality in statice, sufficient basis to reject the null hypotheses.