Compatibility of Entomopathogenic Fungi, Beauvaria bassiana (Bals. -Criv.) Vuill. and Metarhizium anisopliae (Metchn) Sorokin Isolates with Different Agrochemicals Commonly Used in Vineyards

Compatibility studies of biological control agents with different agrochemicals have paramount importance to provide proper guidelines for their integrated use and time of application of these agents. The effect of twenty-one different agrochemical formulations commonly used in vineyards including 10 fungicides, 5 insecticides, 2 acaricides and four plant growth regulators on conidial germination and vegetative growth of entomopathogenic fungi; B. bassiana MN710408 and M. anisopliae MN710409 was tested under laboratory conditions. The results of this study showed that among tested fungicides, copper hydroxide formulation was highly compatible with both fungal isolates, it even stimulated conidial germination at all tested concentrations. Also, Copper- sulphate® showed a high stimulant effect with B. bassiana isolate and to a lesser extent with M. anisopliae isolate. The neonicotinoids were compatible with both fungal isolates at certain concentrations. Lufenuron® showed a stimulation effect to both fungal isolates. Regarding plant growth regulators, the Dormex® formulation completely inhibited conidial germination and vegetative growth of both fungal isolates at field recommended concentration, while other types of these agrochemicals showed various degrees of compatibility depending on the fungal isolate.


Agrochemicals, Fungicides;
Insecticides; Plant growth regulators; Entomopathogenic fungi; Beauvaria bassiana and Metarhizium anisopliae Compatibility studies of biological control agents with different agrochemicals have paramount importance to provide proper guidelines for their integrated use and time of application of these agents. The effect of twenty-one different agrochemical formulations commonly used in vineyards including 10 fungicides, 5 insecticides, 2 acaricides and four plant growth regulators on conidial germination and vegetative growth of entomopathogenic fungi; B. bassiana MN710408 and M. anisopliae MN710409 was tested under laboratory conditions. The results of this study showed that among tested fungicides, copper hydroxide formulation was highly compatible with both fungal isolates, it even stimulated conidial germination at all tested concentrations. Also, Copper-sulphate ® showed a high stimulant effect with B. bassiana isolate and to a lesser extent with M. anisopliae isolate. The neonicotinoids were compatible with both fungal isolates at certain concentrations. Lufenuron ® showed a stimulation effect to both fungal isolates. Regarding plant growth regulators, the Dormex ® formulation completely inhibited conidial germination and vegetative growth of both fungal isolates at field recommended concentration, while other types of these agrochemicals showed various degrees of compatibility depending on the fungal isolate.

INTRODUCTION
Compatibility between entomopathogenic fungi (EPF) with different agrochemical is considered essential for IPM. One of the most important factors affecting the efficacy and stability of (EPF) is the side effect of various agrochemicals used in different agrosystem. (Mietkiewski et al., 1997;Klingen and Haukeland, 2006;Mochi et al., 2006). Toxicity of such agrochemicals to EPF may vary with fungus species or strain, chemical nature of the active ingredient, mode of action and recommended labeling rate (Alves and Lecuona, 1998).
Fungicides were among the first of these agrochemicals which attracted attention since they can affect negatively EPF in several ways. The adverse effects of fungicides depend on fungi species, the type of fungicide the dosage of the active ingredient and the temperature. The inhibitory effect was much greater against the entomophthorales than against the Hyphomycetes. The dithiocarbamate derivations zineb + copper oxychloride, and mancozeb completely inhibited germination B. bassiana, M. anisopliae. Also, the fungistatic effect was more pronounced at 15°C than at 25°C (Majchrowicz and Poprawski, 1993). Moorhouse et al. (1992) mentioned that the fungicides chlorothalonil and zineb prevented germination of M. anisopliae conidia at the commercial concentration; moreover, the carbendazim, totally inhibited growth at 0.1 times the recommended rate. Also, vegetative growth was completely prevented by the fungicides zineb. Kouassi et al. (2003) demonstrated that copper-oxide, metalaxyl, and mancozeb at recommended field rate inhibited the radial growth of B. bassiana (MK2001 isolate) 8 days post-treatment on the solid media.
Concerning insecticide formulations, Urs et al. (1967) demonstrated that BHC ((Lindane) 50% WP and malathion completely inhibited vegetative growth of Beauvaria bassiana and Metarhizium anisopliae in all tested concentrations. Conversely, Dimecron stimulates the growth of both fungi at all concentrations. In vitro, chlorpyrifos completely inhibited the germination of B. bassiana (CG 425strain), and contrariwise, abamictin and pyrethroid formulations were more compatible with B. bassiana (De Oliveira et al., 2003;De oliveira and Neves, 2004). Fiedler and Sosnowska (2017) mentioned that the imidacloprid (Confidor 200 SL) had low toxicity to the B. bassiana fungus. Gamma and lambda-cyhalothrin had the lowest adverse effect on conidial germination of the different isolates of B. bassiana and M. anisopliae, while Significant differences were obtained in the vegetative growth of different fungal isolates (Pelizzaa et al., 2018).
With regard to plant growth regulators (PGR), Storey and Gardner (1986) stated that mefluidide was compatible with B. bassiana since it caused no significant inhibition of germination and growth of the fungus, but the mortality of fall armyworm, Spodoptera frugiperda (Smith) resulting from B. bassiana treatment was significantly reduced when larvae were exposed to conidia plus soil treated with paclobutrazol.
This work aims to evaluate the effect of some agrochemicals commonly used in vineyards on conidial germination and vegetative growth of entomopathogenic fungi; B. bassiana 3873 PSA and M. anisopliae 5130.

Fungal Isolates:
Experiments were carried out under laboratory conditions. Two fungal isolates of entomopathogenic fungi; B. bassiana 3873 PSA and M. anisopliae 5130 PSA were obtained from the collection of Assuit University Mycology Center (AUMC). The identity of these isolates was confirmed using molecular techniques. Both fungal isolates were inoculated on sterilized potato dextrose agar medium (PDA) and incubated at 27°C for one week. Then the aerial mycelium was scraped from the culture surface using a sterile scalpel blade. Total DNA was extracted from fungal cultures by using a commercial plant DNA extraction kit (DNeasy Plant Mini Kit, Qiagen, Germany) following the manufacturer's protocol. The experiment was carried out at a plant quarantine pathogens laboratory; Agriculture Center Research (PQPL). The extraction of isolated DNA was done according to a commercial animal and fungi DNA preparation kit protocol (Jena Bioscience, Germany). Genomic DNA was used as a template for PCR amplification of ITS region, using universal primers ITS1 (5′TCC GTA GGT GAA CCT GCG G 3′), and the reverse primer ITS4 (5′TCC TCC GCT TAT TGA TAT GC 3) (White et al., 1990). The sequencing was performed at Macrogen Company, Korea, and submitted to GenBank (accession numbers MN710408 for B. bassiana and MN710409 for M. anisopliae).

Preparation of Media with Agrochemical Formulations:
Twenty-one of Different agrochemical formulations including 10 fungicides, 5 insecticides, 2 acaricides and four plant growth regulators were evaluated for compatibility with B. bassiana and M. anisopliae the same as described by Kos and Celar (2013).
Firstly, PDA medium was prepared and sterilized in an autoclave at 120 º C for 15min., and cooled to 50-60 º C. Then four concentrations FR, 0.5× FR, 0.25× FR and 0.125× FR from each of fungicides, insecticides, acaricides and only one concentration (FR) of plant growth regulators were prepared by serial dilution and added to PDA media. PDA media with the tested agrochemicals, in addition, to control treatment without additive agrochemicals were poured in three replicates of Petri dishes for each concentration. The Trade names, active ingredients, recommended rates, of the evaluated agrochemicals in this study were listed in Table (1).

Effect of Agrochemicals on Conidial Germination:
Conidial suspensions of each fungal isolate were prepared by flooding 20-day cultures with sterile distilled water. The resulting conidial suspensions were filtered through layers of muslin to remove mycelial mats, and then the suspensions were centrifuged at 5,000 rpm for 15 min. the supernatant was decanted and the conidial mass was re-suspended in aqueous solution of 0.01% Tween 20. The stock suspensions of each fungal isolate were subjected to serial dilutions. According to Anderson and Roberts (1983), the dilution giving above 200 colonies of both fungal isolates per plate was used in all further tests.
The Petri dishes containing PDA medium with tested agrochemicals at different concentrations were inoculated with 10µl of the diluted fungal suspension. Petri dishes were held at 25°C, and the colony-forming units (CFU) were counted after 48h by a microscope at 40× magnification. Treatments were repeated three times. The means of CFU (± S.D.) for each treatment were compared with those for the control treatment. The germination inhibition percentage was calculated as follow:

Effect of Agrochemicals on Vegetative Radial Growth:
Agar plugs (0.8 cm diameter) with B. bassiana and M. anisopliae isolates placed in the middle of Petri dishes (9 cm diam.) containing PDA medium with the tested agrochemicals at the selected concentrations, in addition to the control treatment without additive agrochemicals. Then the Petri dishes were incubated at 25°C. The colonies growth was examined daily for 15 days of culturing to measure the colony diameter. Measurements were taken with a mill metric ruler along the same pre-marked radial axis. The replicated values recorded at each reading were averaged (cm ± S.D.). Each treatment was performed in three replicates (Hokkanen and Kotiluoto, 1992). The inhibition/increase percentage of radial growth of each fungus was estimated as follow:

Statistical Analysis:
The data obtained from various treatments were subjected to a log (X + n) transformation to stabilize the variance and avoid zero values according to (Draper and Smith 1981). The transformed data were carried out in replicated randomized complete block design (RCBD) and submitted to analysis of variance ANOVA, general linear model (GLM), and treatment means were post-hoc compared by the Tukey HSD test with the level of significance p < 0.05. Statistical analysis was conducted by using SPSS version 16.

RESULTS
The compatibility of B. bassiana (MN710408) and M. anisopliae (MN710409) with 21 agrochemical formulations commonly used in vineyards were studied in vitro. The agrochemical formulation included 10 fungicides, 6 insecticides, 2 acaricides and 4 plant growth, regulators. The compatibility was measured by two parameters, conidial germination and mycelial growth.
As shown in Table (2), the in vitro, the viability of the fungal conidia in the presence of copper fungicides showed that Zoom ® based on copper-hydroxide had a stimulating effect on conidial germination of both fungal isolates at all tested concentrations. The stimulation was relatively higher in B. bassiana isolate than the isolate of M. anisopliae. The highest percentage of stimulating in conidial germination over control was 74% in B. bassiana isolate and 29.3% in M. anisopliae at 0.25×FR and 0.5×FR concentrations, respectively. Also, the Copper sulphate ® formulation had also a positive effect on conidial germination of B. bassiana isolate since the stimulatory effect increased linearly by serial dilution of the formulation. The highest percentage of increase in conidial germination over the control (+34.3%) was recorded at the lowest tested concentration. The same formulation had an inhibitory effect on conidial germination of M. anisopliae estimated by -34.7% at FR concentration, and mitigated to -10.3% by diluting the concentration to 0.5×FR. However, it showed a stimulant effect being estimated at 14.6% and 24% at the lower concentrations of 0.25×FR and 0.125×FR, respectively.
Adversely, the copper-oxychloride formulation, Copperarikh ® , had the largest inhibitory effect among the Copper fungicides on conidial germination of both examined fungi. The formulation completely inhibited the conidial germination of B. bassiana isolates at all tested concentrations, except the lowest one which caused 93% inhibition of conidial germination. Also, the Copperarikh ® had an adverse effect on conidial germination of M. anisopliae isolate, but the effect was lower compared with that of B. bassiana isolate. The inhibitory effect on conidial germination increased gradually with doubling the concentration to record the highest percentage (100%) at FR concentration. Micronized Soreil KZ ® , sulfur-based formulation, completely inhibited the conidial germination of B. bassiana isolate independent of concentration, while the inhibition percentage of M. anisopliae conidial germination associated with fungicide concentrations. The inhibitory effect was (100%) at FR concentration, while greatly reduced to -12.7% at 0.125×FR concentration and recorded the highest percentage of inhibition The treatments contain the fungicide Zenga ® had an inhibitory effect on conidial germination of both fungal isolates in a dose-dependant manner, but the inhibition percentage of B. bassiana isolate was higher than that of M. anisopliae isolate. The conidial germination of both B. bassiana and M. anisopliae isolate was inhibited by 56.4 and 95.9 over the control treatment, respectively when exposed to FR concentration. The inhibitory effect of this fungicide was mitigated gradually by reducing the concentration reaching 30.3 and 13.6% at the lowest concentration for B. bassiana and M. anisopliae, respectively. On the other hand, the conidial germination of both fungal isolates was completely inhibited by exposure to the fungicides; Ridomil ® MZ, Tilt ®, Topsin ® M, Nasr Zim ® and Rizolex-T ® . The fungicidal effect of these formulations was independent of their concentration since the lowest (0.125×FR) concentration of the aforementioned formulations showed the same effect.
With regard to the second parameter, vegetative radial growth, the statistical analysis showed that a significant difference in vegetative radial growth of B. bassiana MN710408 in relation to the examined fungicides, F (10, 108) = 380.800, p<0.0001and its concentration F (3, 108) = 25.114, p<0.0001 compared to the control. The radial growth of M. anisopliae MN710409 isolate also affected significantly by fungicide formulation, F (10, 108) =126.331, p<0.001 and its concentration, F (3, 108) = 11.867, p< 0.0001. Data obtained in Table (2) showed that the inhibition effect of copper hydroxide formulation (Zoom ® ) on B. bassiana isolate was significant at FR concentration, in comparison to control, while no effect was found at the three other concentrations. On the other hand, this formulation has no adverse effect on the mycelial growth of M. anisopliae isolate at FR concentration, but it showed a stimulatory effect at all other tested concentrations compared with control. Both copper-sulphate ® and copperoxychloride (Copperarrikh ® ) formulations showed inhibition activity to the mycelial growth of both fungal isolates. The variation in mycelial growth inhibition depends on the fungal isolate, the fungicide formulation and the tested concentrations. The coppersulfate had an inhibitory effect on colony diameter of both fungal isolates, except with the lowest concentration where the mean colony diameter ranged from 5.4-6.8 and 4.1-6.7cm for B. bassiana and M. anisopliae isolates, respectively. Zenga ® formulation showed an inhibitory effect on B. bassiana isolate and stimulatory effect on M. anisopliae isolate where the mean radial growth of mycelium ranged from 5.4-6.4 and 6.7-6.8cm for B. bassiana and M. anisopliae isolates, respectively. Also, Micronized Soreil KZ ® and Ridomil ® MZ caused an inhibitory effect on mycelia growth of both fungal isolates, and complete inhibition has occurred at FR concentrations.
Concerning the Topsin ® , Nasr Zim ® , Rizolex ® and Tilt formulations, it was found that the mycelial growth of both B. bassiana and M. anisopliae isolates was completely inhibited at all tested concentrations of Topsin ® , Nasr Zim ® and Rizolex ® . Tilt ® formulation completely inhibited mycelial growth of M. anisopliae isolate at all tested concentrations, while the mycelium of B. bassiana isolate showed insignificant response by gradual dilution of concentration in comparison with control.

Table (3): Compatibility of insecticides and acaricides with B. bassiana and M.
anisopliae isolates based on conidial germination and mycelial growth.
Mean number ± standard deviation calculated from three replications, means followed by the same letter in each column are not significantly different (p < 0.01, Tukey test).FR=field recommended concentrations, 0.5 ×FR= half field recommended concentrations, 0.25× =one-fourth FR field recommended concentrations and 0.125× one-eighth field recommended concentrations.
Data obtained in Table (3) indicated that the neonicotinoid Sunclopride ® was a germination potent stimulant to conidia of B. bassiana isolate at 0.125×FR concentration since the germination increased by 80% over the control treatment. It relatively inhibited the conidial germination at all other concentrations. The highest percentage of inhibition was 38.9% over the control treatment at FR concentration. On the other hand, the same formulation affected positively the conidial germination of M. anisopliae isolate, except at the highest concentration which inhibited the germination with 10.6% over the control. The highest percentage of conidial germination stimulation in M. anisopliae isolate over the control was +34.8% at the lowest concentration of Sunclopride ® .
The other neonicotinoid formulation, Telphast ® , showed an inhibitory effect on conidial germination of both fungal isolates at the higher concentrations. The inhibitory effect of Telphast ® on B. bassiana isolate was higher than that of M. anisopliae isolate, where the inhibition percentages were 39.4 and 9.6% over the control at FR concentrations for B. bassiana and M. anisopliae, respectively. Contrary, this formulation had a stimulating effect on conidial germination of B. bassiana and M. anisopliae isolates at the lower concentrations. The highest stimulating effect occurred at the lowest concentration (0.125×FR) with percentages of 19.9 and 12.7% on B. bassiana and M. anisopliae, respectively.
Concerning the organophosphate based formulations, Tockthion ® and Ictafos ® had a negative effect on conidial germination of B. bassiana isolate. The inhibitory effect of Tockthion ® was independent of concentration, while the Ictafos ® formulation strongly inhibited the conidial germination at all concentrations, except at the lowest concentration. The conidial germination of M. anisopliae was highly affected by Tockthion® and Ictafos®. The conidial germination of M. anisopliae isolate was completely inhibited by Tockthion® at FR and 0.5×FR concentrations, and this effect decreased at the other concentrations to record the lowest percentage of inhibition (41.6%) at 0.125×FR concentration. On the other hand, Ictafos ® formulation had a highly negative effect on M. anisopliae conidial germination, where it was completely inhibited at all tested concentrations, except at the lowest one since the inhibition of conidial germination was estimated by 6.2% which was on par with the control treatment. Contrary, both fungal isolates showed a positive response to Lenoflag ® treatment at all selected concentrations. The highest stimulatory effect was recorded on conidial germination of B. bassiana isolate by 40.5% at 0.25×FR, while the germination of M. anisopliae conidia recorded a lower stimulating percentage being estimated by 28.7% at the lowest concentration (0.125×FR) of the formulation.
Concerning the acaricide formulations, Arrow ® had also a positive effect on conidial germination of B. bassiana isolate even at FR concentration. The highest percentage of increase of conidial germination was 62.9% over the control at 0.125×FR concentration. The stimulatory effect of this formulation decreased gradually by reducing the concentration to record the lowest percentage of stimulation (28.5%) at FR concentration. On the other direction, M. anisopliae isolate showed high sensitivity toward this acaricide formulation as it had an inhibitory effect in all tested concentrations. The highest percentage of conidial germination inhibition was -74.4% at FR concentration and mitigated gradually by diluting the concentration. The other acaricide formulation Artox ® showed a high stimulation effect (+57.3%) on conidial germination of B. bassiana isolate at the lowest tested concentration. At 0.5×FR and FR concentrations, the formulation showed a reverse effect where it inhibited the conidial germination by -17.7% at FR concentration. Also, the high stimulating effect of Artox ® formulation on conidial germination of M. Anisopliae isolate was recorded at FR concentration and estimated by +33.2% increase over control, while this effect decreased gradually by reducing the concentration to record the lowest percentage of stimulation (14.8%) at 0.125×FR concentration.
As shown in Table (3), The Tockthion®, Ictafos ® , Sunclopride ® and Artox ® formulations inhibited the mycelial growth of both fungal isolates by varied percentages according to the fungal isolate, the insecticide or acaricide formulation and the tested concentrations. The highest inhibition percentages were obtained at FR concentration of Tockthion ® , followed by Ictafos ® being estimated by (82, 65.7 and 71.0, 100%) for B. bassiana and M. anisopliae isolates, respectively. Linoflag ® and Arrow ® formulations showed low inhibition at high tested concentrations and stimulatory effect at the lowest tested concentrations (0.125×FR) on both fungal isolates. Conversely, The Telphast® treatment resulted in stimulation of mycelial growth of both fungal isolates at all tested concentrations, except at FR and 0.5×FR concentrations with B. bassiana isolate being estimated by 11.9 and 4.5% inhibition for both concentrations, respectively.

Effects of Plant Growth Regulators:
The statistical analysis showed that a significant difference in the germination of B. bassiana MN710408 in relation to the examined plant growth regulators, F (4, 10) = 108.635, p<0.0001 compared to control. The conidial germination of M. anisopliae MN710409 isolate also affected significantly by plant growth regulators formulation, F (4, 10) =959.428, p<0.001 and its concentration.
As shown in Table (4), the plant growth regulators (PGRs) formulations were tested at FR concentration. The results showed that the Dormex ® formulation had fungicidal effect on both fungal isolates since the germination was completely inhibited. The gibberellic acid-based formulation Gibbest ® stimulate the conidial germination by +27% and +3% for B. bassiana and M. anisopliae isolates respectively. The Ethrel ® formulation had significant stimulatory effect being estimated by 41.7% on conidial germination of B. bassiana isolate, while the same formulation inhibited conidial germination of M. anisopliae isolate by -24.7% over the control. The Magictone ® formulation caused inhibition in conidial germination of B. bassiana isolate by -45.7% over the control at FR concentration. Conversely, the same formulation stimulated the conidial germination of M. anisopliae isolate significantly by +22.9% over the control. The statistical analysis showed that a significant difference in vegetative radial growth of B. bassiana MN710408 in relation to the formulation of plant growth regulators, F (4, 10) = 390.125, p<0.0001. The radial growth of M. anisopliae MN710409 isolate also affected significantly by plant growth regulators, F (4, 10) =423.109, p<0.001. Data obtained in Table (4) showed that all tested plant growth regulators had an inhibitory effect on mycelial growth of M. anisopliae isolate. The highest inhibitory effect was caused by the Dormex ® formulation (100% inhibition), followed by Magictone treatment (27.5% inhibition). On the other hand, the Dormex ® and the Gibbest ® formulations caused inhibition on mycelial growth of B. bassiana isolate being estimated by 100 and 5.9% for both formulations, respectively. Conversely, the Ethrel ® and Majictone ® showed a stimulatory effect on mycelia growth of B. bassiana isolate being estimated by 8.9% stimulation.

DISCUSSION
The effect of agrochemical formulations on conidial germination/viability of EPF was considered one of the most important aspects in field compatibility evaluation (Anderson and Roberts, 1983;Malo, 1993;Neves et al., 2001). Moreover, fungal conidia is responsible for the preservation of the fungal inoculums in field (Alves and Leucona, 1998).
In the present study, the inhibitory or stimulatory effect of agrochemicals currently used in vineyards on conidial germination and vegetative growth of B. bassiana (MN710408) and M. anisopliae (MN710409) was dependent on fungus species, formulation of agrochemicals and the concentration in the culture medium which agrees with (Vanninen and Hokkanen, 1988;Anderson et al., 1989;Hedimbi et al., 2008;Tkaczuk et al., 2016;Tkaczuk and Majchrowska-Safaryan, 2020). The evaluation of currently used copper formulations revealed that copper-hydroxide (Zoom ® ) was highly compatible with both fungal isolates where it was a potent stimulant of conidial germination of both fungal isolates especially B. bassiana isolate, also Copper-sulphate ® showed a high stimulant effect with B. bassiana isolate and to a lesser extent to M. anisopliae isolate. Conversely, copper-oxychloride (Copperarikh ® ) strongly inhibited the conidial germination of B. bassiana.
The germination stimulatory effect of Copper-hydroxide and copper-sulphate was proceeding in a non-linear manner. A number of authors mentioned that copperhydroxide had a little inhibitory effect on B. bassiana compared to Copper-oxychloride (Olmert and Kenneth 1974;Jaros-Su et al., 1999;Majchrowicz and Poprawski 1993;Tamai et al., 2002;Martins et al.,2012). Similarly, Sosa- Gomez (1991), and Sosa- Gomez et al. (1987) found that copper-oxychloride completely suppressed conidial production of H. thompsonii, while mycelial growth was only reduced. They also mentioned that Copper-sulphate had a fungicidal effect since conidial germination of the fungus was completely inhibited. By contrast with the present results, Challa and Sanivada (2014) demonstrated that Copper-oxychloride promoted the mycelia growth in many isolates of B. bassiana. Celar and Kos (2020) reported that Copper-hydroxide 50% WP caused 79.9% inhibition in vegetative growth and 99.1% inhibition in conidial germination of the commercial strain of B. bassiana ATCC 74040.
The sulphur formulation Micronized Soreil KZ ® completely inhibited the germination of B. bassiana isolate even the lowest concentration while conidia and mycelium of M. anisopliae isolate showed some tolerance to this formulation by diluting of concentrations. This result agrees with Shaha et al. (2009) who mentioned that sulphur inhibited B. bassiana and L. longisporum, but had a mild inhibitory effect on M. anisopliae. On the contrary, Usha et al. (2014) demonstrated that sulphur displayed high compatibility to all isolates of B. bassiana even at high concentrations. Similary, Tkaczuk et al. (2016) reported that the Sulphur-based fungicide; Siarkol Extra 80 WP slightly limited the growth of fungal colonies of Isaria fumosorosea and B. bassiana and at lower concentrations showed even a stimulating effect which disagrees with the present findings.
The Ridomil ® formulation is a mixture of the acylalanine (metalaxyl) and the dithiocarbamate; mancozeb (maneb+zineb) completely inhibited the germination of both fungal isolates even at one-eighth of FR concentration. Although the mycelium of both isolates showed some tolerance to this formulation, the inhibitory effect was significant compared to the control. These findings were consistent with previously published by Machowicz-Stefaniak (1980) since they reported that maneb (0.5%) was harmful to B. bassiana and V. lecanii (over 99% reduction in the beneficial capacity of the fungi). Majchrowicz and Poprawski (1993) mentioned that dithiocarbamates completely suppressed B. bassiana and M. anisopliae. Wie et al. (2004) elucidated that mancozeb completely inhibited the germination of the entomophthorelean fungus Panadora nouryi even at the manufacturer's lowest recommended concentration for field operation. In addition, Khan et al. (2012) demonstrated that metalaxyl (0.1%) and mancozeb (0.2%) were not compatible with B. bassiana and M. anisopliae since they caused complete inhibition of vegetative growth and spore germination. The same effect of mancozeb on B. bassiana was reported by Challa and Sanivada, 2014;Ondráčková et al., 2019). The results showed that the fungicide Zenga ® had a lower adverse effect on conidia and mycelium of both fungal isolates than Ridomil ® formulation which might be due to the presence of copper in the formulation.
The results showed that the fungicides formulations based on propiconazole triazole derivative (Tilt ® ), thiophanate-methyl (Topsin ® M), carbendazim (Nasr Zim ® ) and tolclofos-Methyl 20%+ Thiram 30% (Rizolex-T ® ) had the highest detrimental effect on conidial germination and mycelium growth of both fungal isolates even at high dilution rate which revealed a potential incompatibility of these fungicides with the tested fungal isolates. Earlier, Samuels et al. (1989) pointed to the compatibility of Tilt ® fungicide with certain isolates of M. anisopliae and they suggested that selection of tolerant strains could overcome the problem of incompatibility in-field application. Hassan et al. (1991) showed that bitertanol, a triazole-derived fungicide, was highly toxic to V. lecanii, but less to B. bassiana. Majchrowicz and Poprawski (1993) reported that triazole derivative, triadimefon completely inhibited B. bassiana and M. anisopliae at field recommended concentration. Similarly, Khan et al. (2012) mentioned that members of triazole group including tebuconazole hexaconazole, propiconazole and difenoconazole were not compatible with B. bassiana and M. anisopliae and caused complete or strong vegetative growth inhibition and spore germination. Silva et al. (2013) mentioned that the triazoles difenoconazole and propiconazole reduced conidial germination, mycelial growth and conidiation and should not be applied together with Metarhizium anisopliae. A more recent study by Joshi et al. (2018), showed that propiconazole 25% EC completely inhibits germination of B. bassiana and M. anisopliae in its action at all concentrations. Olmert and Kenneth (1974) showed that B. bassiana was highly sensitive to Carbendazium which agrees with the present findings. Usha et al. (2014) evaluated Bavistin ® ; carbendizam based formulation, where they demonstrated that the conidial germination of all tested fungal isolates of B. bassiana was completely inhibited at field recommended concentration. Fabrice et al. (2013) showed that thiophanate-methyl Topsin ® was able to inhibit the germination of M. anisopliae in the presence of 200 μg/ml of thiophanate-methyl.
The heterocyclic nitromethylenes or neonicotonoids Sunclopride ® and Telphast ® were highly compatible with tested isolate of M. anisopliae and to a lesser extent with the fungal isolate of B. bassiana. These results are supported by Neves et al. (2001) since they elucidated that acetamiprid (Saurus 200 SP), imidacloprid (Confidor 700 WDGr) and thiamethoxam (Actara 250 WG) had no effect on conidia germination of B. bassiana, M. anisopliae and Paecilomyces sp except under the highest concentration of acetamiprid (1.3×field recommended concentration "FR") in which significant inhibition of M. anisopliae occurred. Cuthbertson et al. (2005) mentioned that acetaimprid formulation had a significant inhibitory effect on vegetative growth of B. bassiana and M. anisopliae even at the lowest concentration (0.7×FR). The conidial germination of L. muscarium was reduced by 73.5%. Alizadeh et al. (2007) reported that the inhibition caused by imidaclopride formulation was lower than 27% compared to the control treatment. Khan et al. (2012) stated that acetameprid (0.004%), thiomethoxam (0.005%), imidachloprid (0.005%) were highly safe and most compatible B. bassiana and M. anisopliae. Also, the imidachloprid based "Confidor 200SL" showed low toxicity to B. bassiana even at 1.5 times the recommended field concentration (Fiedler and Sosnowska, 2017).
The present findings emphasized the adverse effect of organophosphate formulations Tockthion ® and Ictafos ® on conidial germination and vegetative growth of both fungal isolates suggesting that combined application with these formulations is best avoided. These results agree with those obtained by Urs et al. (1967) who mentioned that malathion completely inhibited germination of B. bassiana and to M. anisopliae while it permitted limited vegetative growth at low concentrations. The Dichlorvos and chloropyrifos formulations at recommended dosages had a strong inhibitory effect on the growth of Verticilium spp. (Olmert and Kenneth, 1974). The organophosphate compounds directly interfere with cell wall formation due to inhibition of the enzyme that converts phosphatydilethanalamine into chitin. The same mechanism of inhibition was probably responsible for the drastic reduction in B. bassiana conidia germination, vegetative growth and sporulation (Ghini and Kimati, 2000). The conidial germination of B. bassiana (CG 425strain) was completely inhibited by triazophos, chlorpyrifos formulations. With regard to the concentration of the formulation, Amutha et al. (2010) rated chlorpyrifos 20EC as less toxic to B. bassiana while profenophos 50%EC was highly toxic. Usha et al. (2014) mentioned that chloropyrofos was extremely toxic to different isolates of B. bassiana.
The Lufenuron" benzoylureas" based formulation Lenoflag ® acts as IGR by inhibiting synthesis of chitin (Ben-Ziony and Arzi, 2001). The present outcomes indicated that Lenoflag ® was one of the compatible and germination stimulating formulations to both tested fungal isolates. Similar results were obtained by Scotty et al. (2005) who indicated that lufenuron had no effect on the vegetative growth of Aspergillus spp. and Fusarium spp. Hector et al. (2005) stated that lufenuron had no antifungal properties against Coccidioides immitis G.W. Stilies and Aspergillus fumigates Fresenius. Alves et al. (2011), mentioned that the compatibility of lufenuron with M. anisopliae was dose dependant since no interfered with conidia germination of M. anisopliae when used in a concentration of 1 mg/ml and increased it in a concentration of 700 µg/ml. Adversely, diflubenzuron showed high inhibition percentage to L. lecanii (Hall, 1981). Flufenoxuron inhibited the germination of B. bassiana by 96% compared to control (Alizadeh et al., 2007), and hexaflumuron completely inhibited the germination of M. anisopliae (Rashid et al., 2010).
Concerning acaricide, (Arrow ® ), abamectine based ormulation was a potent stimulant of B. bassiana isolate, while mycelium of the same isolate was significantly inhibited at FR and half of FR concentrations. On the other direction, the same formulation significantly inhibited the conidial germination of M. anisopliae isolate, while mycelium was more tolerant to this formulation even at the FR concentration. De oliveira and Neves (2004) mentioned that fenpyroximate and abamectin caused a less detrimental effect on conidial germinationof B. bassiana than fenpyroximate. Conversely, abamectin had a more inhibitory effect on vegetative growth than fenpyroximate.
The Dormex ® , hydrogen cyanide (HC), completely inhibited germination and vegetative growth of both tested isolates suggesting simultaneous use is best avoided. This formulation is frequently used to break dormancy in grapevine floral buds and various deciduous fruits and commonly used as a nitrogen fertilizer with herbicidal and fungicidal effects (Amberger, 2013). No literature mentioned the effect of this formulation on entomopathogenic fungi, however, Spence et al. (2014) found that Magnaporthe oryzae (Hebert) M.E. Barr infecting rice was negatively impacted by hydrogen cyanide. The gibberillic acid formulation was compatible with tested isolates of B. bassiana and M. anisopliae. The Ethrel ® formulation was compatible with B. bassiana isolate, and was a perceptible stimulant of its germination, while it reduced conidial germination of M. anisopliae. Conversely, the Magictone ® had a significant inhibitory effect on conidial germination of B. bassiana isolate, and had a stimulatory effect on conidial germination of M. anisopliae isolate. Results partially agree with those obtained by Khan et al. (2012) who mentioned that, In vitro, naphthalene acetic acid, Ethrel® were compatible with B.bassiana and M. anisopliae. The vegetative growth of B. bassiana and M. anisopliae was enhanced by the plant growth regulator Ethrel, IAA (Indol acetic acid, and NAA (Naphthalene acetic acid).
Based on the previous studies, the stimulatory effect of certain formulations to conidial germination or vegetative growth of fungal isolate may be due to utilizing the released compounds from agrochemical metabolism or substances present in the agrochemical formulation and can be used directly as a nutrient by the fungus. Also, the fungus could be making a reproductive effort, thus increasing conidial production (Moino and Alves, 1998). On the other hand, Boucuas et al. (1998) indicated that either ionic or molecular formulations may neutralize the electrostatic charge of the surface and/or remove the mucous layer covering conidia, thus affecting the substrate recognition process and the transduction of the signal that initiates germination.
The contrasting themes between present results and previous researches outcomes may due to specific differences between tested fungal isolates, the type of formulation besides the concentration of active indigents in each formulation, Generally, wettable powders and flowable formulations cause no inhibition and often increase colony counts whereas, emulsifiable concentrate formulations frequently inhibit B. bassiana germination (Anderson et al., 1989). Adjutants in wettable powders and flowable formulations may act as mild abrasives and break up agglomerations of conidia, which would improve the field performance of B. bassiana.