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.     

Yield,size, and mushroom solids content of <Emphasis Type="Italic">Agaricus bisporus</Emphasis> produced on non-composted substrate and spent mushroom compost

Three crops of Agaricus bisporus were grown on non-composted substrate (NCS), spent mushroom compost (SMC), a 50/50 mixture of NSC/SMC, or pasteurized Phase II compost. 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 were non-supplemented or supplemented with Target^® (a commercial delayed release nutrient for mushroom culture) or soybean meal at spawning or casing, or with Micromax^® (a mixture of nine micronutrients) at spawning. Mushroom yield (27.2 kg/m²) was greatest on a 50/50 mixture of NCS/SMC supplemented with 10% (dry wt) Target^® at casing. The same substrate supplemented with Target^® at spawning yielded 20.1 kg/m². By comparison, mushroom yield on Phase II compost supplemented at casing or at spawning with Target^® was 21.6 kg/m² and 20.6 kg/m², respectively. On NCS amended with 0.74% or 0.9% Micromax^® at spawning, yields increased by 51.8% (12.9 kg/m²) and 71.8% (14.6 kg/m²), respectively, over non-amended NCS (8.5 kg/m²). Conversely, mushroom yields were not affected when Micromax^® was added to a 50/50 mixture of NCS/SMC. Mushroom solids content was higher in mushrooms harvested from NCS amended with 0.74% Micromax^® (9.6%) compared to non-amended NCS (8.3%).     

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.     

Substrate dependent larval development and emergence of the mushroom pests Lycoriella auripila and Megaselia halterata

Pasteurized, spawned, full-grown and immediately-cased full-grown compost were simultaneously exposed to natural populations of the mushroom pests Lycoriella auripila (Winnertz) (Diptera: Sciaridae) and Megaselia halterata (Wood) (Diptera: Phoridae). Different numbers of adults emerged from each of these composts. Highest numbers of L. auripila emerged from spawned and pasteurized compost whereas lowest numbers of L. auripila emerged from full-grown compost. the emergence from full-grown compost was delayed, which could be explained by the delayed development of the larvae in this type of compost. High numbers of M. halterata emerged from compost that was completely colonized by the mycelia of the edible white button mushroom Agaricus bisporus (Lange) Imbach. The immediate covering of the compost with a casing layer significantly lowered the numbers of emerging M. halterata flies. Compared with the emergence pattern from full-grown and immediately-cased full-grown compost, adult M. halterata showed a delayed pattern of emergence in spawned compost. Adult M. halterata did not emerge from pasteurized compost. The results of these experiments enabled us to improve the timing of the application of insect pathogenic nematodes in the control of the larvae of both insect pests.     

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.     

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.     

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.     

Variation of Pleurotus ostreatus (Jacq. Ex Fr.) P. Kumm. (1871) performance subjected to differentdoses and timings of nano-urea

Supplementation of the growing substrate by nitrogenous additives has been known to improve the production of oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm. (1871)). However, the application of nano-additives has not been reported in such cultivation yet. The study investigated the effect of nano-urea added in two different doses (3 g and 5 g per kg substrate), once (at spawning or after first flush) or twice (at spawning and after first flush) to the growing substrate consisting of wheat straw and spent oyster substrate (1:1, w/w). Results showed that the application of nano-urea once has induced the highest number of mushroom flushes (four flushes) despite the dose applied. Contrarily to early findings, where high doses of nitrogen have caused inhibition of mushroom growth and production, nano-urea application has had better effects when applied twice. With 5 g/kg, it induced the shortest period between the first and the third flush (15 days). With 3 g/kg, it resulted in the highest biological and economic yields at the third flush (332.7 g/bag and 283.1 g/bag respectively), in total (973.4 g/bag and 854.0 g/bag respectively), the highest biological efficiency (109.6%), and pileus diameter/stipe length ratio (2.8). Experimental findings of the current study may be potentially applied at commercial scale.     

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.     

Principles of insecticide action on mushroom cropping: incorporation into casing

The incorporation of organophosphorous insecticides into the casing layer of mushroom beds reduces the numbers of mushrooms, according to a logistic relationship with log₁₀ (dose). The cumulative numbers at any flush are affected in this way, and the response of individual flushes may, therefore, be represented by the difference between two logistic curves. This explains the observed increases in numbers in the second and third flushes following diazinon treatment and in the fourth following thionazin, pirimiphos-methyl and pirimiphos-ethyl. No compensation in numbers followed chlorfenvinphos treatment. This decreasing response pattern reflected the increasing residual action of the insecticides. Mushroom size was inversely related to numbers but even when numbers in any flush were unaffected by the treatment, there was usually an increase in size. Thus yield increases occurred in most flushes at commercial concentrations of four insecticides (thionazin compensated only in the fourth flush) and total yields were increased by 8 to 13%.     

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.     

蘑菇渣堆肥对华北落叶松移植容器苗生长和营养积累的影响

为缓解草炭大量使用带来的环境问题,在华北落叶松容器育苗过程中添加蘑菇渣堆肥以替代草炭,添加蘑菇渣堆肥体积比例分别为0%(T₀)、15%(T₁)、18.75%(T₂)、25%(T₃)、37.50%(T₄)、50%(T₅)、56.25%(T₆)、60%(T₇),研究不同配比下基质的理化性质以及对华北落叶松1年生移植容器苗生长和营养积累的影响.结果表明: 当蘑菇渣堆肥替代草炭的比例≤50%时,苗木苗高、地径和生物量与常用草炭处理无显著差异,且处理T₂、T₄、T₅苗木体内养分浓度显著高于对照,基质pH值处于微酸性或中性范围,适宜苗木生长;当蘑菇渣添加比例＞50%时,基质pH值偏碱性,苗木生长受到不利影响,苗木质量下降.当蘑菇渣添加比例为15%时,苗木质量最好,苗高、地径和单株生物量达到最大.因此,蘑菇渣替代草炭培育华北落叶松移植容器苗是完全可行的,替代比例最高可达到50%,当添加比例为15%时,可培育出高质量的苗木.     

Biological control of <Emphasis Type="Italic">Bradysia matogrossensis</Emphasis> (Diptera: Sciaridae) in mushroom cultivation with predatory mites

Larvae of Sciaridae flies (Diptera) cause considerable damage to the mushroom Agaricus blazei (Murrill) ss. Heinemann in Brazil. Brazilian growers have had considerable difficulties in controlling this pest. The objective of this work was to test the effect of the predatory Laelapidae mite Stratiolaelaps scimitus (Womersley) as a control agent of Bradysia matogrossensis (Lane) in cultures of A. blazei. The work corresponded to an evaluation of the efficiency of that predator when released in boxes containing each about 15 L of commercial mushroom compost naturally infested with the pest. The results showed a significant effect of that predator on the population of B. matogrossensis. The release of either 665 or 1330 S. scimitus per box significantly reduced the pest population to levels that, according to grower's experience, apparently could not cause considerable damage. The positive results obtained warrant the conduction of complementary studies to determine the lowest rates of the predator that could still produce acceptable levels of control.     

Influences of compost and casing layer depths on the mechanical properties of mushrooms

The mushroom growing bed consists of an underlying compost which is covered with casing (a peat and chalk or lime mixture) to induce fruit-body formation. The influences of the depths of the compost and casing layers on the mushroom texture, susceptibility to bruising, and ease of detachment from the growing bed surface were investigated. Textural properties were determined on cubes of cap tissue and detachment torque was determined by using an instrumented rotating suction cup which was lowered on to the caps. The proportion of mushrooms which detached at the base from the bed surface was recorded, since this is an important parameter for an automatic (robotic) harvesting system. Shallow casing resulted in mushrooms that were firmer and less likely to deform plastically, but that showed greater discolouration after a standard bruising treatment. Shallower casing also increased the proportion of mushrooms that detached at the base. Increasing the depth of compost produced firmer mushrooms, significantly increased the detachment torque and reduced the proportion of mushrooms detached at the base. The proportion of mushrooms that detached at the base correlated negatively with the plastic deformation of cap tissue. A positive correlation was found between mushroom dry matter content and tissue firmness.     

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.     

Properties of peat-based casing soils and their influence on the water relations and growth of the mushroom (Agaricus bisporus)

Different combinations of peat and chalk or lime sources with differing moisture contents were used to determine how specific physical and chemical properties of the casing soil relate to the growth and water relations of the mushroom. The peat types varied in terms of decomposition and extraction method; the lime addition varied in terms of rate and type (chalk or sugar beet lime). During the colonisation of the casing soil before fruiting, the extension growth rate of mushroom mycelium was most closely correlated (negatively) with the volumetric moisture content of the casing soil. Scanning electron microscopy showed that mycelium growing at a lower casing soil matric potential (Ψ_m) had a much finer and branched structure than mycelium growing at a higher Ψ_m. Across all the peat and lime source treatments, a relationship was found between the mean Ψ_m of the casing soil and mushroom yield, with an optimum Ψ_m of -7.9 to -9.4 kPa. Mushrooms are produced in ‘flushes’ at about 8-day intervals and during the development of each flush of mushrooms, there was a significant decrease in casing soil Ψ_m . This decrease (to below -40 kPa) was greatest in the second flush, which was the highest yielding. There were no relationships between mushroom yield and casing soil osmotic potential Ψ_π within the range -93 to -154 kPa or any of the other chemical properties and water and air holding characteristics of the casing soils which were determined. Across different casing soil treatments, mushroom dry matter content was negatively correlated with mushroom yield and positively correlated with mushroom tissue osmotic potential. This revised version was published online in June 2006 with corrections to the Cover Date.     

Production of Agaricus bisporus on substrates pre-colonized by Scytalidium thermophilum and supplemented at casing with protein-rich supplements

The objective of this study was to evaluate performance of Agaricus bisporus (Ab) on substrates pre-colonized by Scytalidiumthermophilum (St), a thermophilic fungus known to enhance yields of Ab and increase selectivity of the substrate. The radial extension rate (RER) of the mycelium of three strains of St and their influence on the growth of a brown strain of Ab were evaluated. We also determined the time required for colonization of pangola grass by St in a compost pile and the influence of three protein-rich supplements on yield of Ab on pangola grass (Digitaria decumbens) colonized by St. RER of St ranged from 10.1 mm/d on grass to 18.9 mm/d on potato dextrose yeast extract agar, with significant differences among substrates and among strains. Ab grew faster on substrate colonized for 1, 2, or 3 days by St (RER of 3.31, 3.29, 3.23 mm/d, respectively) compared to non-colonized substrate (1.85 mm/d). Ab was cultivated on substrate samples selected daily from the St-inoculated pile, with biological efficiencies (BE) ranging from 4% (day 0) to 73.9% (day 2). Protein-rich supplements (soybean, black beans and cowpeas) added at casing significantly stimulated mushroom yield on St-colonized substrate compared to the non-supplemented control. BE varied from 26.1% on substrate non-supplemented to 73.1% on compost supplemented with ground soybean. There were no significant differences in mushroom yield observed among supplements evaluated.     

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.     

Influence of Steinernema feltiae and Diflubenzuron on Yield and Economics of the Cultivated Mushroom Agaricus bisporus in Dutch Mushroom Culture

The insect pathogenic nematode Steinernema feltiae (Nematoda: Steinernematidae) was shown to offer an alternative to the use of diflubenzuron for the control of the mushroom fly Lycoriella auripila (Diptera: Sciaridae). The influence of diflubenzuron and S. feltiae treatments on the yield and numbers of the mushroom, Agaricus bisporus , was studied. Applications of diflubenzuron after casing significantly reduced total mushroom yields by 10-13%. The greatest yield reductions were observed in the first flush. In the second flush, high yields were found despite significantly lower numbers of mushrooms. These high yields, however, could not compensate for the yield loss of the first flush. Some of the treatments with S. feltiae significantly increased yields, but these were not associated with a particular time of application. As nematodes did not reduce mushroom yields they were able to compete with diflubenzuron. Although the purchase costs of nematodes were high, their use was more economical than that of diflubenzuron when the yield losses of 10% due to casing treatments were taken into account.     

Degradation of Metsulfuron Methyl by Agaricus blazei Murrill Spent Compost Enzymes

Metsulfuron methyl (MM) is an herbicide used in cereal crops. The white rot mushroom Agaricus blazei Murrill is an important edible and medicinal mushroom reported to be a major laccase producer, a lignin-degrading enzyme with low substrate specificity. A search for assaying the potential use of A. blazei spent mushroom compost (SMC) as a remediation tool for cleaning MM polluted soils was carried out. A phytotoxic dose of this herbicide was separately incubated with two enzyme preparations obtained from the SMC after the second mushroom fruiting flush; the phytotoxicity of the resulting reaction mixtures was then assayed by using a plantlet growing test with Brassica napus L. Thus, the crude enzyme SMC extract preparation (I) or the partially purified enzyme SMC extract (II) and their dilutions, 1:10 and 1:100, were mixed with MM (5 × 10^?3 ppm final concentration) and incubated at 25°C for 24, 48, 72, and 96 h. Plantlets separately exposed for 72 and 96 h to the resulting reaction mixtures between MM and those enzyme preparations showed a highly significant increase in their hypocotyl length with respect to plantlets exposed to MM alone. It was thus demonstrated the ability that complex enzyme fractions present in A. blazei SMC have to degrade MM during the right incubation time to compounds with no or lower phytotoxicity than this herbicide.