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Tuta absoluta, an economically important pest threatening the global production of tomato crops worldwide, has recently invaded China. Owing to insecticide resistance, alternative control options are needed within the context of integrated pest management (IPM) programs. Augmentative biological control using indigenous natural enemies is a promising tactic for managing T. absoluta in newly invaded areas. In this study, the host suitability of four commercialized Trichogramma parasitoids in China (T. dendrolimi, T. japonicum, T. chilonis, and T. ostriniae) on T. absoluta eggs was evaluated in laboratory conditions. The control effectiveness of the most promising Trichogramma species was further tested at different release densities and frequencies in a greenhouse experiment. We found that T. chilonis was the most promising species parasitizing T. absoluta eggs, showing the highest parasitism rate, emergence rate, and female offspring sex ratio. The greenhouse experiment indicated that 600,000 parasitoids/hectare (20 parasitoids/plant) was the most effective release density, reaching 76% control effectiveness. Release frequency significantly affected the parasitism rate in the greenhouse. Two releases of 300,000 parasitoids/hectare on Day 1 and Day 4 was the most effective strategy, compared to one release of 600,000 parasitoids/hectare on Day 1. Our findings showed that augmentative biological control of T. absoluta by native Trichogramma parasitoids T. chilonis in China is feasible, and it could be included as part of IPM package against T. absoluta in China. [ABSTRACT FROM AUTHOR]

A 16-week incubation experiment was conducted to determine the pattern of nitrogen (N), phosphorus (P), and sulphur (S) mineralization in soils treated with poultry manure slurry (PMS), poultry manure with bedding (PMB), cattle manure (CM), horse manure (HM), rabbit manure (RM), swine manure (SM), and goat and sheep manure (GSM) applied at 120 kg N ha−1. The concentrations of nitrate–N (NO3-N), ammonium-N (NH4-N), total mineral nitrogen (TMN), available P, and S were determined fortnightly. Result showed that SM and HM had significantly (p ≤ 0.05) higher C:N, C:P, C:S, N:P and N:S than other manures. The percentage of TMN, P, and S mineralized was in the order of SM > CM > HM > GSM > RM > PMB > PMS. From 8 to 14 weeks, SM, CM, HM, GSM, and RM exhibited net negative ammonification, while net positive nitrification of NO3-N occurred from 6 to 14 weeks of incubation in all manures. Soil treated with SM had a significantly higher proportion of total mineral N, available P, and S by 24, 54, and 45%, respectively. PMS had the highest mineralization and concentration of TMN, P and S; and peak at 10, 8, and 6 weeks, respectively. NO3-N was the dominant form of total mineral N (R2 = 0.99), and positive correlation occurred between TMN and cumulative P (R2 = 0.82) and S (R2 = 0.94). The study concluded that manure quality and properties are good predictors of N, P, and S mineralization. [ABSTRACT FROM AUTHOR]

Biochar is a pyrolyzed product of organic matter having enormous potential for nutrient loading and enhancing nutrient use efficiency. In the present study, two enriched biochar (EB)-based fertilizers were prepared, having a fertilizer grade of 6–6-4 N-P2O5-K2O by intercalation of NPK fertilizers mixture solution as EB-1 and additional humic acid and seaweed extract with EB-1 as a formulation of EB-2. The batch experiments were conducted to compare nutrients (NH4+, NO3−, P, and K+) release patterns of developed fertilizers with conventional fertilizers. Enriched biochar fertilizers (EB) demonstrated a much slower release pattern of NH4+, P, and K+, but NO3− release was similar to conventional fertilizers. The total release of N from EB fertilizers was like conventional fertilizer; however, significantly less P and K were released during the period of 36 h. The field response study in direct-seeded rice revealed that the application of EB fertilizers 11.7–29.5, 32.9–64.0, and 31.4–38.0% higher apparent use efficiency of N, P, and K, respectively than conventional fertilizer at 100% application rate. This implies the possible utilization of EB fertilizers in sustainable rice production with reduced losses and enhanced nutrient use efficiency (NUE). [ABSTRACT FROM AUTHOR]