The effect of sciarid larvae (Lycoriella auripila) on cropping of the cultivated mushroom (Agaricus bisporus)

Significant linear relationships between the mean number of sciarid, Lycoriella auripila, larvae/125 g-sample of casing and yield, numbers of mushrooms and weight/mushroom were demonstrated at all stages of a mushroom crop. Negative relationships were obtained for yield throughout the cropping period. There was no injury threshold for this pest, although an economic threshold of one larva/sample was deduced. Loss in yield was mostly due to the destruction of mushroom primordia and presumed interruption of nutrient supply to the developing sporophores. Numbers of mushrooms were severely reduced in the first, second and third flushes, more so than yield, although a large increase in numbers was demonstrated in the fourth flush. The size of mushroom was inversely related to numbers, although the increases in size in the first three flushes were insufficient to compensate for the reduction in numbers. A reduction in size was evident in the fourth flush.     

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.     

Submerged growth of the cultivated mushroom,Agaricus bisporus

Agaricus bisporus grew well in submerged culture in a medium containing malt extract, phosphate, and casein. Moderate growth occurred in defined media containing glucose, asparagine, phenylalanine, vitamins and minerals. Other amino acids did not stimulate growth. Growth was stimulated by vegetable oils, partly due to utilization of the oils, and partly to a more complex mechanism. Oleates had the same effect as vegetable oils; palmitates a lesser one. In shaken flasks maximum yield was reached after 22–24 days and in stirred and aerated fermentors after 8–10 days. Besides dry weight of mycelium, laccase activity was determined. The latter determination is suitable for a rapid estimation of the growth in routine experiments. The flavour of the mycelium was like that of mushrooms but weaker. It was strongest in standing liquid cultures and on solid media. The mycelium grown in submerged culture was suitable as spawn for mushroom culture. Presented at the First International Mycological Congress, Exeter, 7–16 September 1971, and at the Meeting of the Netherlands Society for Microbiology, Rotterdam, 8 December 1971. We thank the Mushroom Experiment Station, Horst, the Netherlands, for kindly supplying the compost for fructification experiments and Mr. P. Arntz, M.Sc., for advice in the fermentor work. F. IJ. Dijkstra is indebted to the Royal Netherlands Fermentation Industries (Gist-Brocades), Delft, for a research grant.     

Studies on Hot Water-soluble and Dilute Alkali-soluble Polysaccharides from the Fruit Body of Mushroom (Psalliota campestris (Linn) Fr.)

The effect of apple polyphenol extract (APE) on the proliferation and invasion of a rat ascites hepatoma cell line of AH109A was examined in vitro. APE suppressed both the hepatoma proliferation and invasion in a dose-dependent manner up to 200 μg/ml. Serum obtained from rats orally given APE also inhibited hepatoma proliferation and invasion when added to the culture medium. Subsequently, the effect of dietary APE on growth and the metastasis of AH109A hepatomas were investigated in vivo. APE reduced the growth and metastasis of solid hepatomas and significantly suppressed the serum lipid peroxide level in rats transplanted with AH109A. APE also suppressed the serum very-low-density lipoprotein + low-density lipoprotein (VLDL + LDL)-cholesterol level. These in vitro and in vivo findings suggest that APE has anti-hepatoma activities.     

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.     

Cultivation of the oyster mushroom (Pleurotus ostreatus) on wood substrates in Hawaii

Summary Five non-native, aggressively growing trees, Falcataria moluccana (Miquel) Barneby & Grimes, Casuarina equisetifolia L. ex J. R. & G. Forst, Eucalyptus grandis Hill ex Maid, Psidium cattleianum Sabine, and Trema orientalis (L.) Blume, were evaluated for suitability as substrate for outdoor cultivation of the oyster mushroom, Pleurotus ostreatus (Jacq.: Fr.) Kumm., in Hawaii. An existing shade house was modified for mushroom production and proved to be an adequate fruiting site. Nitrogen-fixing trees (C. equisetifolia, T. orientalis, and F. moluccana) supported greater yield (275.5, 272.4 and 268.8 g/bag, respectively), biological efficiency (70.1, 78.5, and 74.0%, respectively), and flush number (3.0, 3.2, and 3.5) than non-fixers. P. cattleianum supported significantly lower yield (190.5 g/bag) and biological efficiency (44.2%). Mean crop period was 51 days and was not affected by the wood substrate. Similarly, substrate did not have a significant impact on the concentration of nutrients or moisture in fruit bodies. Taste preferences were noted in mushrooms grown on different substrates; those grown on C. equisetifolia were most flavourful and preferred in one taste test.     

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.     

Resistance of bioincised wood treated with wood preservatives to blue-stain and wood-decay fungi

Bioincising is a biotechnological process that aims at the improvement of wood preservative uptake in wood species with a low permeability, such as Norway spruce (Picea abies (L.) Karst). The process is based on a short-term pre-treatment with white-rot fungus Physisporinus vitreus. During incubation the membranes of bordered and half bordered pits are supposed to be degraded by fungal activity resulting in a better treatability of the wood structure for wood preservatives. In the present study, first of all the resistance of bioincised Norway spruce heartwood and untreated controls against blue-stain and wood-decay fungi (white- and brown-rot) was determined. Then, bioincised and untreated specimens were dipped or vacuum impregnated with six wood preservatives and substance uptake was assessed gravimetrically. Additionally, the penetration of 3-iodo-2-propynyl butylcarbamate (IPBC) into the wood was analyzed by high-pressure liquid chromatography (HPLC). Finally, wood resistance was assessed according to the European standards EN 152 and EN 113. Results showed no difference between bioincised wood without preservatives and the untreated wood against blue-stain discolouration. However, a significant (P < 0.05) increase in susceptibility against wood decay was recorded. In the bioincised wood samples a significantly higher uptake of all the different preservatives was determined and the HPLC-method revealed that IPBC penetrated deeper into bioincised wood than into control samples. The improved uptake of preservatives into bioincised wood resulted in a significantly higher resistance against white- and brown-rot fungi. However, only a slight protection against wood discolouration by blue-stain fungi was recorded. The results of this study show for the first time that the biotechnological process with P. vitreus can be used to improve wood durability by increasing the uptake and penetration of wood preservatives.     

A classification of the stages in the growth cycle of the cultivated paddy straw mushroom (Volvariella volvacea singer) and its commercial importance

The developmental stages in the growth of the cultivated paddy straw mushroom (Volvariella volvacea) on damp straw beds were studied. Pure cultures of the strain CI/70/52 were grown on test tube slants of potato dextrose sugar, and the inoculum increased in large bottles filled with moistened paddy straw. The bottle inoculum was used to inoculate three layers of a four-tiered straw bed. The stages in the development of a carpophore were classified on the basis of the time sequence, length, breadth and length/breadth ratio. The results suggest that the classification provides a basis for harvesting the buttons at the most desirable stage.     

Effects of cultural conditions on the mycelial growth of healthy and virus-infected cultivated mushroom, Agaricus bisporus

There was a significant inverse correlation (P= 0=001) between concentrations of mushroom viruses 1 and 2 in sporophores and amounts of mycelial growth on malt agar of isolates taken from them. Increasing virus concentrations decreased linear growth of one mushroom strain from 76 mm (healthy) to 35 mm (mildly infected) and 7 mm (severely infected) when incubated at 25°C for 3 wk. Mycelial growth rates of isolates from healthy and from virus-infected mushrooms were compared on eleven agar media. All media clearly differentiated between healthy and severely infected isolates, but fewer separated healthy from mildly infected isolates. Those that did contained maltose, sucrose or starch as carbon source. Media containing peptone usually gave better differentiation than those with other sources of nitrogen, but the best differentiation was obtained with malt agar. Growing healthy and infected isolates on a range of media affected their subsequent growth on malt agar, the growth of some isolates apparently being changed permanently after 2 months on some of the different media. Whereas none of the infected isolates grew less rapidly after this treatment, the growth of some of the mildly infected isolates improved to such an extent that they could no longer be distinguished from healthy isolates. After heat-treatment (1–6 wk at 33°C), mycelial growth rates of infected isolates were increased, but viruses 1 and 2 were not always eliminated unless the heat-treatment was begun immediately after subculture. Mycelial growth rate and colony characters are not infallible criteria of the presence or absence of virus, a feature of particular significance when checking the health of mushroom spawn.     

The comparative effects of three formulations of diazinon on cropping of a hybrid and a non-hybrid strain of the cultivated mushroom Agaricus bisporus

Three formulations of diazinon: flowable granules (FG); wettable powder (WP); and emulsifiable concentration (EC), which are used for the control of mushroom pests, were compared for toxicity towards a hybrid and non-hybrid strain of the cultivated mushroom, Agaricus bisporus. With all formulations, yield and number of mushrooms were reduced according to dosage (linear trend). The EC was the most toxic and persistent formulation – equally so to both mushroom strains – and produced the most severe responses in all the parameters considered. The WP was the least toxic formulation. The hybrid strain was more susceptible to diazinon than the non-hybrid, but not markedly so.     

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.     

Effect of spent mushroom compost tea on mycelial growth and yield of button mushroom (Agaricus bisporus)

Preliminary studies suggested that the use of compost tea made from spent mushroom substrate (SMS) may be regarded as a potential method for biologically controlling dry bubble disease in button mushroom. The aim of this study was to assess the effect of SMS compost tea on the host, the button mushroom, to ascertain whether the addition of these water extracts has a toxic effect on Agaricus bisporus mycelium growth and on mushroom yield. In vitro experiments showed that the addition of SMS compost tea to the culture medium inoculated with a mushroom spawn grain did not have an inhibitory effect on A. bisporus mycelial growth. The effect of compost teas on the quantitative production parameters of A. bisporus (yield, unitary weight, biological efficiency and earliness) was tested in a cropping trial, applying the compost teas to the casing in three different drench applications. Quantitative production parameters were not significantly affected by the compost tea treatments although there was a slight delay of 0.8-1.4 days in the harvest time of the first flush. These results suggest that compost teas have no fungitoxic effect on A. bisporus so that they can be considered a suitable biocontrol substance for the control of dry bubble disease.     

Comparative effects of Steinernema feltiae (Nematoda: Steinernematidae) and insecticides on yield and cropping of the mushroom Agaricus bisporus

In a mushroom crop (Agaricus bisporus) affected by a very low level of sciarid fly (Lycoriella auripila) infestation, the effects of an indigenous isolate of insect-parasitic nematode (Steinernema feltiae) and of two commonly used insecticides (diazinon and diflubenzuron) were studied. When compared with untreated plots, nematodes applied to the casing had no adverse effects on mushroom yields whereas insecticides decreased yields. At a rate of 3 × 10⁶ infective juveniles per tray (surface area = 0.56 m²), S. feltiae elicited increases of 28.5% and 19% in the mean total numbers and weights of mushrooms respectively. Treatment only with diflubenzuron resulted in 14.6% and 6% reductions in mean total numbers and weights of mushrooms, respectively; treatment with both diazinon and diflubenzuron caused 18.5% and 9.4% losses. Application of nematodes generally reduced the mean weight per mushroom whereas insecticides increased it; nematodes delayed the onset of mushroom production (first flush) whereas diflubenzuron delayed the third and fourth flushes. Nematode contamination of sporophores was minimal when S. feltiae was applied at casing. Although their numbers declined with time, the nematodes persisted, in the casing layer, throughout the cropping period of seven weeks. It is concluded that yield benefits associated with nematode application can result mainly from nematode effects on A. bisporus and not solely from suppression of a damaging pest population.     

Isolation and characterization of membranes from the cultivated mushroom

The membranes of sporophore cap tissue from the cultivated mushroom, Agaricus bisporus (Lange) Sing., were isolated using discontinuous sucrose gradient ultracentrifugation of a tissue homogenate. A membrane-rich fraction was concentrated at the 1.16/1.18 g/cc interface and a mitochondria-rich fraction at the 1.18/1.20 g/cc interface. The membrane fraction was judged to be greater than 90% membrane vesicles by electron microscopy. The protein to lipid ratio of the membrane fraction was 1.1; the molar ratio of sterol to phospholipid was 0.77. The specific radioactivity of a Mg-activated ATPase was 2.5 times greater in the membrane fraction than in the homogenate. No 5′-nucleotidase or Na-K-Mg-activated ATPase activity was observed.     

The effect of viruses on growth and cropping of pear trees

Two virus diseases, vein yellows and mosaic, that commonly infect pear trees, reduced the growth and crop of four cultivars (Beurré Hardy, Doyenne du Cornice, Conference and Williams' bon Chrétien) in an experiment continued for 13 years. Reduction in yield was mainly due to the smaller size of infected trees. These produced about 30% less fruit than healthy trees when infected with vein yellows and 40 % less fruit when also infected with mosaic. Fruit size was decreased in only one year. The fertility of Cornice flowers was impaired. The greater vigour of healthy trees did not delay cropping; they produced over 30% more fruit than infected trees in the first three harvests.     

The effect of various microelements on changes in the activity of certain enzymes in hydroponically cultivated barley during the first period of growth

The paper deals with the effect of the application of certain ions (Zn²⁺, B₄O₇ ^2- Mn²⁺, Cu²⁺, MoO₄ ^2-,) on the development of the activity displayed by amylase, urease, and glutamate-oxalacetate (GOT) in hydroponically cultivated barley during the first seven days of ontogenesis. The enzymes were studied separately in the overground and root parts of the plants. The following main conclusions can be drawn from the findings made: The amylase activity of the control plants in connection with their development diminished slightly in the overground part, while it was relatively constant in the roots. Due to the effect of certain elements tested, this activity increased pronouncedly (significant differences were confirmed in variants containing MoO₄ ^2-, Zn²⁺, and Co²⁺). The urease level in the overground part of the control plants remained low throughout the entire experimental period and was only little influenced by the individual microelements under study (with the exception of B⁴O₇ ^2-). On the other hand, the urease activity in the root system increased markedly, the B₄O₇ ^2- ions exhibiting a significantly stimulating effect. The activity of glutamate-oxalacetate transaminase (GOT) in the overground part of the control plants increased only slightly in the course of the initial development, while in the root system it grew relatively more pronouncedly. In the overground part of the plants all the microelements administered displayed a significantly depressive effect on the development of this enzyme activity; in the roots, the inhibitory action was maintained only in the last experimental period in variants with Zn²⁺ ions.