Individual and combined effects of light-trapping, biological and chemical control on Lycoriella solani (Winnertz) populations in experimental mushroom production cubicles were examined. During three weeks following the introduction of recorded numbers of adult L solani into experimental cubicles, light-traps caught a maximum 74% of¯ies initially released. However, lighttrapping stimulated adult¯y activity and immature stages in the growing substrate throughout the experiment. Consequently, no yield improvements, independently or in combination with biological control agents, were recorded. Incorporation of diazinon (25 mg AI kg À1 ) to compost following pasteurisation did not signi®cantly reduce subsequent emergence of adult sciarids. Additional drench application of di¯ubenzuron (1 g AI m À2) to the casing layer reduced the number of immature sciarids during the ®rst cropping period by 99% (P`0.001). However, inclusion of chemical insecticides reduced the mushroom yield during this period by 14% (P`0.001). Introduction of the predatory mite Hypoaspis miles (Berlese) to the compost during its colonisation by mycelium of Agaricus bisporus (Lange) reduced emergence of adult sciarids by 87% (P`0.05). Later introduction of H miles at the beginning of the case-run period was less effective. Application of the parasitic nematode, Steinernema feltiae (Filipjev (=S bibionis Bovien, after Poinar, 1990)) to the compost during its colonisation by mycelium of A bisporus had no immediate effect on sciarid emergence and provided only limited reduction at later crop stages. Similar application immediately after casing reduced sciarid emergence at ®rst¯ush by 82% (P`0.05). Irrespective of application time, a formulation of Bacillus thuringiensis (Berliner) var israeliensis had no signi®cant effect on sciarid emergence or mushroom yields at any production stage.

The microbial and biochemical characteristics of compost prepared from wheat straw and chicken litter can determine the total yield of fruiting bodies of Agaricus bisporus. With the aim of identifying key substrate parameters and their relationship with mushroom yield, compost samples were obtained from four comparative trials carried out over a seven year period. The objective of this study was to assess the use of near infrared (NIR) reflectance spectroscopy for determining important characteristics of pasteurised compost. The samples were analysed for moisture content, microbial population, pH, conductivity, nitrogen, carbon and hydrogen, nitrogen, ash, ammonia, Na, Cu, Fe, acid detergent fibre, neutral detergent fibre, lignin and fibre fractions as determined by thermal analysis. Results from conventional analytical methods were correlated with NIR data and partial least squares regression analysis used to assess the information in the absorbance spectrum, which determines the concentration of the key parameters. Visible and NIR scans of the calibration samples made over the range of 400-2498 nm indicated that best calibrations could be developed using the 1100-2498 nm segment. NIR calibration equations for predicting NDM, ash, carbon, thermophilic population and fibre fractions have been successfully developed and then validated using independent samples.

Substrates from three mushroom compost facilities in Northern Ireland, employing similar production technologies, were examined to assess the quality of the compost produced. Biochemical investigation highlighted changes in substrates through each step of the production cycle. Thermogravimetric analysis (TGA) provided useful information on fiber fraction content and extent of substrate breakdown. A comparison of productivity, chemical, and thermal data permitted assessment of the degree of bioconversion that had occurred in the decomposition from raw materials to finished substrate for each composter. One of the composters consistently produced substrate of inferior quality compared to the other two, indicating production inefficiencies during composting. Results demonstrated that allied to chemical analyses, TGA is a useful tool, providing valuable information on substrate quality and, in particular, for studying the bioconversion of lignocellulosic materials in mushroom compost.

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The yield of fruiting bodies of Agaricus bisporus from compost is variable due to differences in available nutrients and cultural conditions during production. The objective of this study was to evaluate the use of near-infrared (NIR) reflectance spectroscopy for assessing potential compost productivity. Three compost comparative trials, carried out over the past six years under controlled experimental conditions, have generated a large sample set (48 × 3 = 144) with yield data. Visible and NIR reflectance measurements of the calibration samples were made over the range of 400–2498 nm. A partial least-squares (PLS) algorithm was used to generate the predictive models using the information in the spectrum. A model developed with the spectral region 1100–2498 nm could explain 87% of the variation in mushroom yields obtained from the three trials. The accuracy of the NIR yield model has been confirmed in a validation compost comparative trial. A combined calibration equation (r2 = 0.93) using the spectral data (1100–2498 nm) from the four trials was developed with a standard error of cross-validation of 18.6 kg/tonne.