The influence of spawn type and strain on yield, size and mushroom solids content of Agaricus bisporus produced on non-composted and spent mushroom compost

Two crops of Agaricus bisporus (J. Lange) Imbach were grown on mixtures of non-composted substrate (NCS)/spent mushroom compost (SMC) or pasteurized Phase II compost (control). NCS consisted of oak sawdust (28% oven dry wt), millet (29%), rye (8%), peat (8%), ground alfalfa (4%), ground soybean (4%), wheat bran (9%), and CaCO3 (10%). Substrates included 25/75 NCS/SMC, 50/50 NCS/SMC, and 75/25 NCS/SMC, NCS and Phase II compost. Spawn types and strains were evaluated for their effects on yield, biological efficiency (BE), size and mushroom solids content. Spawn types included millet, casing inoculum (CI), 50/50 CI/millet, or NCS while mushroom strains were of the brown or hybrid off-white variety (U1 type). Mushroom yields and BEs on substrate mixtures of NCS and SMC were comparable to non-supplemented Phase II compost. The highest yield (12.8 kg/m2) and BE (70.9%) were produced on a substrate mixture of 50/50 NCS/SMC and spawn type NCS. Mushroom solids content (7.1%) was highest from the brown strain produced on a 50/50 mixture of NCS/SMC.     

Supplementation of first break mushroom compost with hydrolyzed protein, commercial supplements and crystalline amino acids

Three mushroom (Agaricus bisporus) crops (Crops 1, 2, 3) were grown to evaluate the effects of re-supplementing “spent” first break compost [mushroom compost (MC)] on mushroom yield. Mushrooms were produced for one break at the Mushroom Test Demonstration Facility, the casing layer was removed and the MC was re-supplemented with hydrolyzed protein, commercial supplements and crystalline amino acids and then re-cased at the Mushroom Research Center. Sixteen supplements, including five crystalline amino acids, one amino acid blend, one egg white and four hydrolyzed proteins, Micromax^® (a micronutrient containing nine minerals) and four commercial supplements were evaluated for their effect on mushroom yield and biological efficiency. In Crop 1, mushroom yields were stimulated (49–61%) when MC was re-supplemented with 3.6% (dry wt) Pro-Fam^® H200 FG hydrolyzed soy protein, Remo’s commercial supplement, l-isoleucine (ile), egg white protein, amino blend HLA-198 and hydrolyzed whey. Significant yield reductions were observed for MC re-supplemented with 3.6% l-tyrosine, dl-methionine or l-arginine compared to the non-supplemented control. In Crop 2, mushroom yield ranged from a high of 31.3 kg/m² on MC supplemented with 3.3% Remo’s + 0.3% ile (oven dry MC) to a low of 22.6 kg/m² on non-supplemented (control) MC (38.5% difference). In Crop 3, a response surface model was used in an attempt to optimize combinations of Remo’s commercial supplement, ile and Micromax. The response surface solution for optimal yield was 2.9% Remo’s, 0.16% ile and 0.4% Micromax. Because many of the products tested performed equally well but varied substantially in their amino acid profiles, A. bisporus appears adaptable to different supplements containing both balanced and unbalanced amino acid contents, especially those rich in the branched chain amino acids. Development and improvement of supplements designed specifically for MC may allow further increases in productivity. Double cropping would ultimately lower the cost of mushroom production by reducing labor, raw materials and time required to prepare fresh Phase II compost.     

Factors affecting entomophilic activity of Neoaplectana feltiae in mushroom compost

The host-searching ability of Neoaplectana feltiae Filipjev (= S. bibionis Bovien) (Nematoda: Steinernematidae) in response to larvae of a mushroom fly, Lycoriella solani Winn. was examined in a mushroom substrate. Individuals of L. solani were less attractive for the parasite than larvae of Galleria mellonella L. The nematode juveniles penetrated a 22 cm layer of casing mixture within 2–4 days. In the casing alone nematode effectiveness was better than in mushroom compost or in compost and casing together. In the casing mixture parasite dosages of 20 and 100 juveniles per cm² led to 22% and 45% parasitization of L. solani respectively, while all G. mellonella larvae were parasitized at both dosages. The prevalence of nematode infection depended on the content of water in the mushroom substrate. The highest N. feltiae infectivity was observed, when the ratio of the dry casing weight to the weight of water content was 1: 2.5. The practical aspects of the observed phenomena, essential for the use of N. feltiae in the protection of commercial mushroom cultivation are discussed.     

Bendiocarb and diflubenzuron as substitute insecticides for endosulfan in commercial mushroom growing

Diflubenzuron and bendiocarb treatments of compost and casing soil at a rate of 1 g a.i./m² each, resulted in comparable or even improved compost and casing soil colonisation over endosulfan treatments (at a rate of 1.5 g a.i./m²). Alternating diflubenzuron/bendiocarb treatments were preferable to the reverse treatments, which tended to diminish total yield of mushrooms significantly by 1.4–3.9 kg/m². This effect was due to the casing soil treatment with diflubenzuron and not due to the compost treatment with bendiocarb after spawning. The effectiveness of these substitutes for endosulfan was tested on five commercial mushroom farms, where a similar or improved control of Megaselia halterata (Diptera: Phoridae) was obtained over control (endosulfan) treatments. If present, Lycoriella auripila (Diptera: Lycoriidae) was very effectively controlled by the substitute insecticides compared with endosulfan. Relatively high numbers of M. halterata were occasionally observed in endosulfan-treated houses, indicating that a certain level of resistance towards this insecticide may already have developed. This assessment of tolerance in M. halterata emphasised the need for substitute insecticides with different modes of action, in addition to environmental reasons. The chemicals should be alternately applied within individual crops to avoid resistance development.     

Stimulation of yield in the cultivated mushroom by vegetable oils

Supplementation of mushroom compost at spawning and at casing with various refined and crude seed oils resulted in 1 to 1.5 lb/ft² increases in mushroom yield. Supplementation at casing with ground seeds or protein-oil combinations caused 2 to 2.5 lb/ft² increases in mushroom yield. Further evidence is presented for a relationship between lipid metabolism and the initiation of fruiting in the cultivated mushroom, Agaricus bisporus (Lange) Sing. Preliminary results suggest the possible involvement of sterols in the fruiting stimulation.     

Effects of Caenorhabditis elegans (Nematoda: Rhabditidae) on yield and quality of the cultivated mushroom Agaricus bisporus

Thirteen species of saprobic rhabditid nematodes (11 genera) were identified from samples of compost and casing material collected from mushroom farms in the British Isles. Caenorhabditis elegans, the most frequently found saprobe, was mass-produced monoxenically and its effects on the cultivated mushroom, Agaricus bisporus (strain U3) were studied. C. elegans did not multiply in well-prepared, pasteurised, spawned compost, whereas casing material proved to be a highly suitable environment for its reproduction. An initial casing inoculum of 10⁶ nematodes/crate of compost (7.5 kg), caused a significant reduction in mushroom yield. Losses in total mushroom yields of 11%, 20% and 26% were caused by initial inoculum rates of 10⁶, 10⁷and 2 × 10⁷ nematodes/crate, respectively. Yields were negatively correlated with the initial nematode inoculation level and regression equations were derived. The nematode treatments caused fewer mushrooms to be produced and an absence of the usual distinctive flushing patterns. C. elegans caused considerable deterioration in mushroom quality and characteristic distortion of mushrooms. Individual sporophores were mis-shapen, notched and had brown or violet coloured grills. Up to 3.8%, 6.7% and 10.8% of total weight and 3.5%, 5.4% and 8% of total numbers of mushrooms were distorted at the three highest nematode inoculum rates tested. Weights and numbers of distorted mushrooms were positively correlated with the initial nematode population. C. elegans commonly colonised sporophores.     

Influence of formaldehyde-treated soybean and commercial nutrient supplementation on mushroom (Pleurotus sajor-caju) yield and in-vitro dry matter digestibility of spent substrate

Summary Pleurotus sajor-caju 537 was grown on chopped, pasteurized wheat straw non-supplemented and supplemented with formaldehyde-treated soybean, commercial delayed-release nutrient (SpawnMate II SE) or vegetable oil. Yield was 2.1-fold higher for substrate supplemented (12% dry wt) with low-volume formaldehyde-treated soybean as compared to non-supplemented substrate. Mushroom yield from substrate supplemented with commercial nutrient was 1.7-fold higher than yield from non-supplemented substrate. As the supplement level increased, the mushroom yield response increased. The yield ranged from 3.56 kg/m² for non-supplemented substrate to 7.36 kg/m² for substrate supplemented (12% dry wt) with formaldehyde-treated soybean. The type of supplement affected in vitro dry matter digestibility (IVDMD) of spent substrate; commercial supplement resulted in higher IVDMD compared to formaldehyde-treated substrate. An opportunity exists for commercial development of a nutrient(s) specifically designed for Pleurotus cultivation.     

Some effects of the nematodes Ditylenchus myceliophagus and Aphelenchoides composticola on the yield of the cultivated mushroom

The addition of one, ten and fifty Aphelenchoides composticola per ioo g compost at spawning reduced the total yield of sporophores by 26%, 30% and 42% respectively (P= 0·01), demonstrating a significant regression (P= 0·05) of yield on inoculum concentration. In pots inoculated at spawning with ten and fifty A. composticola per 100 g compost, cropping ceased after 12 weeks. The addition of twenty, 100 and 300 Ditylenchus myceliophagus at casing reduced the total yield of sporophores by 50%, 68% and 75 % respectively (P= 0·01). Cropping did not occur in pots inoculated at spawning, but continued for 9 weeks in pots inoculated at casing. The yield from pots inoculated at casing with either nematode was significantly greater (P= 0·05) than that from pots inoculated at spawning. When inoculated at spawning, peak populations of D. myceliophagus and A. composticola were reached 7 and 13 weeks, respectively, after spawning. Then the numbers present were unrelated to the number in the inocula.     

Effects of the paedogenetic mushroom cecid, Heteropeza pygmaea (Diptera:Cecidomyiidae) on cropping of the cultivated mushroom (Agaricus bisporus)

When introduced into a mushroom crop at rates of 2, 20 or 200 larvae/tray (0.56 m²), the mushroom cecid, Heteropeza pygmaea, caused significant reductions in both yield and number of mushrooms in relation to the infestation level. The reductions were greater when the larvae were introduced at spawning rather than at casing. The yield and number of infested (unmarketable) mushrooms increased significantly in relation to the initial infestation level. Just two H. pygmaea larvae, introduced at spawning, resulted in cecid populations that caused a 12% loss in total yield in addition to a 7% loss due to spoilage. Loss assessment in the future, therefore, should take into account both yield suppression and spoilage. There was little effect of cecid infestation on flush timing and mushroom size was only affected in the fourth flush, when a significant reduction (27%) was shown at the highest infestation rate at spawning.     

Effects of spawn,supplement and phase II compost additions and time of re-casing second break compost on mushroom (Agaricus bisporus) yield and biological efficiency

Three cropping experiments (0710, 0803 and 0805) were conducted to determine the effect of adding spawn, various levels of delayed release nutrient, and phase II compost to 2nd break mushroom compost (2BkC) on mushroom yield and biological efficiency (BE). We also investigated the effect of delaying time of re-casing non-supplemented and supplemented 2BkC on mushroom yields and BEs. The addition of 14.6% spawn to nutrient-supplemented 2BkC (w.w./d.w) increased yield by 11.1% over the control (no spawn) but did not affect BE. The addition of delayed release supplements to 2BkC increased maximum yields by 29–54%, depending on the treatment. Substitution of 15% phase II compost in 2BkC (15/85) did not significantly affect mushroom yields. However, use of 15% phase II compost in 2BkC increased the response of the mixture to delayed release supplement. Yield response to increasing levels of supplement was greater in the 15/85 mixture compared to 100% 2BkC. Yields also increased as time of re-casing was delayed up to 10 days. Mushroom yields increased approximately 2.1% for each day re-casing was delayed. Overall yields were generally higher from commercial 2BkC compared to 2BkC originating from the Penn State Mushroom Research Center (MRC) probably due to nitrogen (N) content of the 2BkC. Nitrogen content in commercial 2BkC (Crop 0805) was 3% while N content in 2BkC from Crops 0710 and 0803 was 2.2% and 2.1%, respectively. By optimizing supplement levels and adding 15% phase II compost to commercial 2BkC, or by delaying casing by 5–10 days, it was possible to obtain BEs that were equivalent to supplemented phase II compost.     

The effect of spent mushroom compost on Lecanicillium fungicola in vivo and in vitro

Leached spent mushroom compost (SMC) and its extract were tested to suppress Lecanicillium fungicola in white button mushroom. Sterile and non-sterile mixture of SMC and peat were used to assess suppressiveness against L. fungicola in greenhouse experiments. The extract of SMC was prepared with sterile, non-sterile, filtered, supplied with nystatin, streptomycin and penicillin antibiotics to evaluate their effect in suppression of pathogen in vitro. Isolated bacteria from SMC extract were tested for antagonism rate against Lecanicillium fungicola. The results of the experiments showed that all applications rate of none-sterile SMC were effective in control of pathogen. However, the sterile SMC amendments did not have a positive effect on the pathogen suppression in vitro or in vivo, as was expected. The treatments amended with SMC 100% and 60% showed the most suppressive effect in the control of pathogen. Using of non-sterile SMC 20%, 40%, 60% and peat soil were most effective in mushroom yield. The extract of leached SMC showed inhibition of L. fungicola in petri dishes. Three bacteria isolated from extract, Bacillus subtilis, Bacillus licheniformis and Bacillus amyloliquefacien identified using 16s rRNA, showed an antagonistic effect with the fungal growth.     

Supplementation of 2nd break mushroom compost with isoleucine, leucine, valine, phenylalanine, Fermenten® and SoyPlus®

Three mushroom (Agaricus bisporus) crops (Crops 1, 2, 3) were grown to evaluate the effects of re-supplementing “spent” mushroom compost (MC) with the crystalline amino acids isoleucine (ile), leucine (leu), valine (val) and phenylalanine (phe) singly or in combination with Fermenten^® or SoyPlus^® on mushroom yield. Fermenten^® is a rumen fermentation enhancer while SoyPlus^® is a commercial delayed release mushroom nutrient. The most important single amino acid found for stimulating mushroom yield from 2nd break MC was ile. Crystalline ile added to 2nd break MC at 3.6% (dry wt) increased mushroom yields by 28.3% and 68.7% (average 48.5%) in Crops 1 and 2, respectively, compared to the non-supplemented control. In Crop 3, the addition of 5% or 10% ile to Fermenten^® and SoyPlus^® (3.6% total combined dry wt) did not significantly improve mushroom yield over treatments containing Fermenten^® or SoyPlus^® (3.6% total dry wt) alone. However, mixtures of equal quantities of Fermenten^®, ile and val significantly increased yield over Fermenten^® alone. Use of ile and val as supplements to stimulate mushroom yield from 2nd break MC is not economically viable because these amino acids are not commercially available at feed grade prices.     

Performance of olive mill solid waste as a constituent of the substrate in commercial cultivation of Agaricus bisporus

The feasibility of using olive mill waste (OMW) as an ingredient in the substrate used for cultivation of Agaricus bisporus (Lange) Sing. was studied in a large-scale cultivation trial, concerning 2500 m² of mushroom growing area, at a specialized mushroom farm. Standard commercial cultivation technique involving compost preparation, spawning, casing and harvesting was used. The performance indicators such as mushroom yield, biological efficiency, market quality as well as horticultural value of the spent compost showed that the compost prepared with OMW was superior to the control compost in all the categories. The OMW-amended substrate supported higher populations of beneficial microorganisms especially, actinomycetes which enabled the breakdown of the compost ingredients. It is suggested that OMW is a suitable ingredient for the preparation of mushroom substrate. We have demonstrated that conversion of OMW (a liability) into value-added mushroom substrate (an asset) is an effective waste management tool in oleaculture.     

Comparative effects of three insect growth regulator insecticides and a dipteran-active strain of Bacillus thuringiensis on cropping of the cultivated mushroom Agaricus bisporus

Three insect growth regulator insecticides and an entomopathogenic strain of Bacillus thuringiensis (GC327), products effective against the mushroom sciarid, Lycoriella auripila, were compared for their effect on mushroom cropping. Cyromazine and diflubenzuron were applied as a surface drench to mushroom compost before or after pasteurisation (at filling or spawning, respectively); admixed into casing material (at casing); or at a combination of these times. Hexaflumuron and GC327 were applied only at filling and casing, respectively. The presence of the target pest, L. auripila, had no effect on treatment trends, although it was accounted for in the analysis by use of a yield model. The trial was notable for the disparate effects that cyromazine and diflubenzuron casing treatments had on mushroom cropping. Cyromazine treatments that included application at casing resulted in increases in yield, compared to the untreated control whereas, with diflubenzuron, the opposite was true, with treatment at casing alone causing the greatest reduction overall (10%). GC327 applied at casing was also conspicuous for giving a 13% increase in yield. Treating the crop at casing with either cyromazine or GC327, therefore, resulted in a 15% or 24% increase in yield, respectively, compared to a similar treatment with diflubenzuron. Hexaflumuron applied at filling caused increases in yield compared to application of cyromazine at filling and cyromazine or diflubenzuron at spawning. There were also effects on crop timing. The addition of a cyromazine casing treatment normally caused the distinct flushes of mushrooms to be produced significantly earlier than the untreated control (up to 2.5 days), as did GC327. With diflubenzuron, the earlier flushes were only produced by those treatments that did not include a casing application. The combinations that included a casing treatment with diflubenzuron initially produced mushroom flushes earlier than the untreated control. They became either synchronous with the control or they were delayed. From the crop tolerance perspective, therefore, cyromazine and GC327 would be the sciarid control products of choice for a commercial mushroom grower.     

Changes in quality of Phellinus gilvus mushroom by different drying methods

This study was conducted to investigate the changes in characteristics of the Phellinus gilvus mushroom as influenced by drying methods after harvest. The lowest weight loss rate of P. gilvus mushroom was 75.8% with drying in the shade and 80% by dryer (60°C). The size loss rate of pileus was 19.3% of that in a hot air dryer (60°C). The hardness of dried material context using a hot air dryer (60°C) was the lowest (20 kg/cm²), and that by a dry oven (60°C) was the highest (457 kg/m²). For ΔE value, 4.9 of context and 2.6 of tubes using drying in the shade (20°C) were found to be the lowest. The survival rate of sarcoma 180 treated with P. gilvus dried in the sun was the lowest (51.8%), and this was considered the most effective method for antitumor activity against sarcoma 180.     

Fruit-body production of a luminous mushroom,Mycena chlorophos

Cultural conditions for fruit-body production ofMycena chlorophos were investigated with the aim of using the mushroom for study of bioluminescence, scientific exhibition, and ecological conservation. A small glass jar having a cap with a microfilter was used as a culture vessel. A compost powder mixed with rice bran in proportion of 20% (fw/fw) and adjusted to 70% (w/w) in moisture content was used as production medium. Casing with 2 g/jar of moistened compost powder was necessary for fruit-body formation. Mycelium was grown in a culture chamber at 27°C, relative humidity (RH) of 80% for 4 wk, then transfered to a culture chamberat 21°C, 90% RH and light intensity of 300–800 lx after casing its, and incubated for 3 wk to produce fruit-bodies. The mean yield was 31 fruitbodies, i.e., 150 mg dry weight per jar.     

Effects of bendiocarb and diflubenzuron on mushroom cropping

When mixed into the casing or compost layers of a mushroom bed in the absence of pests, bendiocarb decreased yield and number of mushrooms according to concentration. The most severe effects were on mushroom number at the two highest rates used (100 and 1000 μg/g), and there were large increases in mushroom size. Effects of bendiocarb incorporation in the compost diminished with time, and there was partial compensation in yield and numbers at the fourth flush. The action of bendiocarb persisted when it was mixed into the casing. Diflubenzuron showed some opposite effects at lower concentrations. When either mixed into, or drenched onto the casing at the commercial rate (30 μg/g), yield and size were both increased and the timing of the flushes was unaffected. At the two higher concentrations (180 and 1080 μg/g), reductions in yield and number and an increase in mushroom size were shown. However, these effects became more severe with time, especially those on mushroom number, possibly due to the accumulation of a toxic breakdown product.     

Susceptibility of mushroom pests to the insect-parasitic nematodes Steinernema feltiae and Heterorhabditis heliothidis

The potential of two species of insect-parasitic rhabditid nematodes (Steinernema feltiae, Heterorhabditis heliothidis) for biological control of mushroom flies was studied in pot trials. Three Diptera that commonly infest mushroom crops were used; the larvae of Megaselia halterata (Phoridae), Heteropeza pygmaea (Cecidomyiidae) and Lycoriella auripila (Sciaridae) were all susceptible to parasitism by both nematode species. Fewer adult phorids and sciarids emerged when compost was nematode-treated and, for L. auripila, the effects of nematode applications at spawning, casing or on both occasions were compared. Casing treatments were more effective than spawning treatments; little extra benefit was gained from applying the nematodes twice. Populations of paedogenetic larvae of H. pygmaea built up rapidly in untreated compost, but were reduced when S. feltiae was applied, and were eradicated by H. heliothidis. Because they can penetrate insect cuticle, as well as natural body openings, Heterorhabditis spp. may be more suitable than Steinernema spp. for the control of mushroom fly larvae.     

Control of the mushroom pests Lycoriella auripila (Diptera: Sciaridae) and Megaselia halterata (Diptera: Phoridae) by Steinernema feltiae (Nematoda: Steinernematidae) in field experiments

The nematode Steinernema feltiae (Nematoda: Steinemematidae) was tested for its ability to control two main mushroom pests i.e. the sciarid Lycoriella auripila (Diptera: Sciaridae) and the phorid Megaselia halterata (Diptera: Phoridae) in growing-rooms filled with spawned compost. A clear difference between female and male sciarid control was observed. A nematode application 1 day after casing preceded by an application 1 day before casing on the compost caused an almost complete control (97%) of the F1-generation of female sciarids. The F2-generation of females was similarly controlled (95%) by an application 7 days after casing. A dosage of 1 × 10⁶nematodes m^-2was found to be equally effective as higher dosages. Diflubenzuron remained active throughout entire the cropping period with high sciarid mortality rates varying from 72% to 99%. Phorid control was variable and seemed to depend on the presence of sciarids. In one occasion the control rate of F2-generation phorid larvae was 75% and was possibly caused by the presence of new infective juvenile nematodes recycled in F2-generation sciarid larvae. Diflubenzuron did not significantly reduce phorid numbers.     

Re-supplementing and re-casing mushroom (<Emphasis Type="Italic">Agaricus bisporus</Emphasis>) compost for a second crop

Experiments were performed to determine the effect of adding nutrient supplements to colonized mushroom compost (MC) for the production of a second crop of mushrooms. Mushrooms were harvested for 1, 2 or 3 flushes, the casing removed and the MC then was fragmented and re-supplemented with delayed release supplements treated or non-treated with fungicide (thiophanate-methyl; Topsin M 70WP) and re-cased. Overall double-crop yields were higher when MC was re-supplemented after 1st flush (1st flush MC) as compared to re-supplementation after the 2nd or 3rd flushes. Mean double-crop BEs were 128, 119 and 109% when 1st-, 2nd- and 3rd-flush MCs were used, respectively. Treatment of delayed release supplement with thiophanate-methyl fungicide did not affect mushroom yields. Soluble salts and potassium concentrations increased 350 and 900%, respectively, in the casing overlay through three flushes suggesting that removal of the casing would help to alleviate the build up of these potential growth-limiting materials. Re-supplementing and re-casing of MC represents a potential opportunity for growers to increase revenues and reduce costs associated with preparation and disposal of compost. The ability to double-crop mushroom compost would provide growers a chance to increase yields by 40% or more, depending on whether they re-supplement and re-case after 1st, 2nd or 3rd flush.