Pollen Alone or a Mixture of Pollen Types? Assessing Their Suitability for Mass Rearing of Neoseiulus cucumeris (Acari: Phytoseiidae) Over 20 Generations

The generalist predatory mite, Neoseiulus cucumeris (Oudemans) is known as one of the most effective natural enemies on many pests. This economically important biocontrol agent was reared for 20 generations on date palm and castor bean pollen as well as a mixture of pollen types, including date palm, castor bean, and almond. The performance of this predator was evaluated by comparing its life table parameters after different generations (G1–G20) fed on each diet in a laboratory at 25 ± 1°C, 60 ± 5% RH, and a photoperiod of 16:8 (L: D) h. The development time of the predator reared on all tested diets had no significant difference in G20. The intrinsic rate of increase (r) of N. cucumeris by feeding on the mixed pollen (0.197 day⁻¹) was significantly higher than that on castor bean, or date palm pollen (0.146 or 0.152 day⁻¹ in G1, respectively). Our results indicated that the predator’s performance was not affected by long-term feeding on the pollen diets, as well as there was no considerable difference between pollen alone and pollen mixture diets. Furthermore, mites reared on pollen diets had higher quality than those reared on natural prey, Tetranychus urticae Koch.     

Effect of the earthworm, eisenia foetida (oligochaeta), on fluxes of volatile carbon and sulfur compounds from sewage sludge

Rates of decomposition, measured by flux rates of CO₂, O₂ CH₄, H₂S, CH₃SH and (CH₃)₂S, and populations of anaerobic bacteria were determined in an activated sludge before and after ingestion by Eisenia foetida. Feces always exhibited higher (P < 0.05) fluxes of CO₂ and O₂ and generally lower (P < 0.05) fluxes of CH₄, H₂S, CH₃SH and (CH₃)₂S than sludge, indicating that E. foetida feeding stimulated aerobic decomposition. For both sludge and feces, decreasing moisture contents resulted in lowered CO₂ and O₂ flux rates. Volatile sulfur compounds produced over 24 days accounted for only 0.02–0.08% of the total S present.Populations of total anaerobes, nitrate reducers, sulfate reducers and methanogens were not significantly affected by either earthworm feeding or moisture content.