versión On-line ISSN 0718-5839
Chilean J. Agric. Res. vol.71 no.4 Chillán dic. 2011
Chilean Journal of Agricultural Research 71(4) October - December
Laboratory Trials of Metarhizium anisopliae var. acridum (Green Muscle®) Against the Saxaul Locust, Dericorys albidula Serville (Orthoptera: Dericorythidae)
Ensayos de Laboratorio de Metarhizium anisopliae var. acridum (Green muscle®) contra la Langosta de Saxaul, Dericorys albidula Serville (Orthoptera: Dericorythidae)
Heydar Valizadeh1, 2, Habib Abbasipour2, Mohammad Mahmoudvand3*, Hassan Askary4, and Vahid Reza Moniri5
1Agricultural and Natural Resources Research Center of Qom, Qom, Iran.
2Shahed University, Faculty of Agricultural Sciences, Postal code: 3319118651 Tehran, Iran.
3Islamic Azad University, Department of Plant Protection, Khorramabad Branch, Khorramabad, Iran, *Corresponding author (email@example.com).
4Iranian Research Institute of Plant Protection, Tehran, Iran.
5Research Institute of Forest and Rangelands, Tehran, Iran.
The saxaul locust, Dericorys albidula Serville (Orthoptera: Dericorythidae) is a major pest of saxaul plants in Qom province of Iran. During 2005-2006, different nymphal instars of bands of D. albidula were treated by aerial spraying of Metarhizium anisopliae var. acridum (Green Muscle®). The gasoline formulation of M. anisopliae var. acridum isolate IMI 330189 was applied in different conidial concentrations (106, 107, 108, 109, 1010 and 1013 spores mL-1) that were prepared in sterile distilled gasoline. Results showed that various concentrations significantly affected the 2nd, 3rd, 4th and 5th nymphal instars of D. albidula compared to control. In addition, there were no differences in the effects of the different concentrations in 2005, but the differences were significant in 2006. Concentration 1010 killed 100% of tested insects 15 d after treatment. Comparing the results of the two years showed that the susceptibility of nymphs in the second year (2006) was higher than in the first year (2005). In conclusion, the results of this study indicated that the fungal insecticide M. anisopliae var. acridum, diluted in gasoline, was efficacious with the nymphal instars of locust D. albidula in 2005 and 2006.
Key words: Saxaul plants, fungal insecticide, nymphal instars, gasoline formulation.
La langosta del saxaul, Dericorys albidula Serville (Orthoptera: Dericorythidae), es la principal plaga de plantas de saxaul de las provincias Qom, Irán. Durante 2005-2006, diferentes instars ninfales de D. albidula se asperjaron con Metarhizium anisopliae var. acridum (Green Muscle®). La formulación de gasolina de M. anisopliae var. acridum aislamiento IMI 330189 se aplicó en diferentes concentraciones conidiales (106, 107, 108, 109, 1010 and 1013 esporas mL-1) preparadas en gasolina destilada estéril. Los resultados demostraron que varias concentraciones afectaron significativamente los nstars ninfales de D. albidula comparado con el control. Además el efecto de concentraciones no fue diferente en 2005 pero sí significativamente en 2006. La concentration 1010 mató 100% de insectos 15 d después del tratamiento. La comparación de los resultados de estos anos mostró que la susceptibilidad de ninfas en el segundo ano (2006) fue mayor que en el primer ano (2005). En conclusión, los resultados de este estudio indicaron que el insecticida fúngico M. anisopliae var. acridum diluido en gasolina tuvo buena eficacia sobre los instars ninfales de langosta D. albidula en los anos 2005 y 2006.
Palabras clave: Plantas de Saxaul, insecticida fúngico, estados ninfales, formulación de gasolina.
The saxaul locust, Dericorys albidula Serville (Orthoptera: Dericorythidae), is a major pest of saxaul plants in Qom province in central Iran. To prevent shifting sands, the desert areas in Qom are covered by two species of saxaul plant, Haloxylon persicum Bunge ex Boiss. & Buhse (zard-tagh in Persian) and Haloxylon ammodendron (C.A. Mey.) Bunge (siah-tagh in Persian). The locust D. albidula is a monophagus pest and feeds on saxaul plants (Haloxylon spp.) and causes severe damage in different growth periods (Adeli and Abaei, 1989; Moniri, 1998). During the last two decades, most outbreaks of D. albidula have likely developed due to of the expansion of cultivated Haloxylon trees. To limit damage to crops, treatment is required virtually every year, usually with large amounts of broad-spectrum chemical pesticides that pollute the environment and present health and safety issues, as well as exacerbating locust problems due to the loss of natural enemies (Moniri et al., 2005).
In recent years, some studies have focused on developing fungal insecticides to control locusts and grasshoppers (Prior, 1992; Moore and Prior, 1993). Four to five hundred species of fungi have pathogenic effects on insects. There are entomopathogenic species among all five sub-divisions of fungi (Mastigomycotina, Zygomycotina, Ascomycotina, Basidiomycotina, and Deuteromycotina) (Burges and Hussey, 1971; Whitten and Oakeshott, 1991; Starnes et al., 1993). Fungi penetrate the insect cuticle. The host can be infected by direct treatment and by transportation of inoculums from treated insects to untreated ones (Lacey et al., 1999; Quesada-Moraga et al., 2004). After attaching itself to an insect host, the conidium penetrates the cuticle with the help of pressure of the germ tube and enzymatic degradation (Starnes et al., 1993). As well, the infection can occur through the respiratory system (Burges and Hussey, 1971). The genus Metarhizium (Deuteromycotina: Hyphomycetes) includes three species: M. anisopliae (Metschn.) Sorokin, M. flavoviride (W. Gams & Rozsypal) and M. album (Petch). Unlike M. anisopliae, which affects a large number of insect orders, the other two species have a more restricted host range (Rombach et al, 1986; 1987). One of the most promising biological agents for controlling locusts and grasshoppers is the Acridid-specific fungal pathogen Metarhizium anisopliae var. acridum (formerly Metarhizium flavoviride) (Ascomycota: Hypocreales) (Langewald et al., 1997; Driver et al., 2000; Hunter et al., 2001; Peng et al., 2008; Bischoff et al., 2009; USDA, 2010). Depending on insect species and size, M. anisopliae results in host death between 3 and 4 d after infection (Whitten and Oakeshott, 1991; Starnes et al., 1993). A variety of this species, M. anisopliae var. acridum, under the commercial name Green Muscle, has been developed to control locusts and grasshoppers (Thomas et al., 2000). Using oil-based formulations has improved the virulence of conidia and resulted in very promising acridid control (Symmon, 1992; Bateman, 1997).
According to the authors' knowledge, reports about D. albidula are limited and there have been no investigations regarding the effect of mycoinsecticide on the species. In this study, we investigated the effect of various concentrations of M. anisopliae on different nymphal stages of D. albidula under laboratory condition over two years.
MATERIALS AND METHODS
The initial population of the locust D. albidula was collected from desert areas in Qom province, Iran. Saxaul bushes (H. ammodendron) were used for feeding and egglaying. Insect stock was maintained at 23 ± 2 °C and 35 ± 5% relative humidity (RH) under a 16:8 (L:D) cycle in a growth chamber.
The miscible flowable gasoline formulation of M. anisopliae var. acridum isolate IMI 330189 with 400 g (2 x 1013) viable conidia per liter was used in the experiments. A spray method was used in the toxicity assays. Different conidial (Green Muscle®) concentrations (106, 107, 108, 109, 1010, and 1013 spore mL-1) were prepared in sterile distilled gasoline. As a control, gasoline was used. Two-year-old saxaul bushes were cultured in plastic pots (15 cm in diameter and 25 cm height) and 10 1-d-old nymphs were placed on each bush. Ten milliliters of each concentration (fungus diluted in gasoline) and control group were sprayed on bushes. The mortality was recorded after 15 d from treatments. The experiments were repeated three times. This method was performed for various nymphal instars (2nd, 3rd, 4th, and 5th).
The data obtained were submitted to a one-way ANOVA (P < 0.05) after checking for normality. Means were compared by Tukey's Studentized Range Test, admitting significant differences at P < 0.05. SAS software was used for all analyses (SAS Institute, 1997).
Insecticidal effect of M. anisopliae on D. albidula in 2005
Figures 1-3 show the effect of various concentrations of M. anisopliae var. acridum on the 3rd (Figure 1) 4th (Figure 2) and 5th (Figure 3) nymphal instars of D. albidula in the first year (2005). Figure 1 reports that various concentrations (106, 107, 108, and 109) significantly affected the 3rd nymphal instars of D. albidula compared to control. In addition, the effect of concentrations was not different (df = 5, 12, F = 10.47, P = 0.0004). Concentrations 109 and 1010 had a significant effect on the 4th nymphal instars of D. albidula (Figure 2). There were no differences among these concentrations (df = 2, 6, F = 108, P < 0.0001). Comparison of toxicity of different concentrations of M. anisopliae var. acridum on the 5thnymphal instars of D. albidula indicated that nymph mortality rates at all concentrations (106, 107, 108, 109, and 1010) were significantly higher than for the control (Figure 3). The toxicity levels of the various concentrations were different but not significant (df = 5, 12, F = 15.54, P < 0.0001).
Figure 1. Toxicity of various concentrations of Metarhizium anisopliae var. acridum on the 3rd nymphal instar of Dericorys albidula (Orth.: Dericorythidae) (2005).
The same letters indicate no significant difference.
Figure 2. Toxicity of various concentrations of Metarhizium anisopliae var. acridum on the 4th nymphal instar of Dericorys albidula (Orth.:Dericorythidae) (2005).
Figure 3. Toxicity of various concentrations of Metarhizium anisopliae var. acridum on the 5th nymphal instar of Dericorys albidula (Orth.: Dericorythidae) (2005).
Insecticidal effect of M. anisopliae on D. albidula in 2006
Nymphal mortality of D. albidula exposed to M. anisopliae var. acridum in 2006 is shown in Figures 4-7. Effect of conidial concentrations on the 2nd nymphal instar of locust showed that all concentrations (106, 107, 108, 109, and 1010) significantly increased mortality of nymphs. Furthermore, there were differences in the insecticidal ability of various concentrations. Concentration 1010 killed 100% of tested insects (Figure 4) (df = 5, 15, F = 238.66, P < 0.0001). Figure 5 shows the mortality trends (to specify the increasing or decreasing trends) of the 3rd nymphal instar of D. albidula after treating by M. anisopliae var. acridum. There was a significant difference between control and all concentrations. As well, the concentration of 1010 caused the highest mortality (100%). Other concentrations also showed high toxicity on the 3rd nymphal instar (Figure 5) (df = 5, 12, F = 71.62, P < 0.0001). The efficacy of conidia of M. anisopliae var. acridum on the 4th instars of locust can be observed in Figure 6. All of the tested concentrations significantly affected the D. albidula nymphs. The highest mortality was observed in the concentration of 1010 and 1013 (Figure 6) (df = 5, 12, F = 76.62, P < 0.0001). M. anisopliae var. acridum in the various doses caused significant mortality of the 5th nymphal instar of D. albidula. As well, there were differences among all concentrations (Figure 7) (df = 5, 12, F = 122.60, P < 0.0001).
Figure 4. Toxicity of various concentrations of Metarhizium anisopliae var. acridum on the 2nd nymphal instar of Dericorys albidula (Orth.: Dericorythidae) (2006).
Figure 5. Toxicity of various concentrations of Metarhizium anisopliae var. acridum on the 3rd nymphal instar of Dericorys albidula (Orth.: Dericorythidae) (2006).
Figure 6. Toxicity of various concentrations of Metarhizium anisopliae var. acridum on the 4th nymphal instar of Dericorys albidula (Orth.: Dericorythidae) (2006).
Figure 7. Toxicity of various concentrations of Metarhizium anisopliae var. acridum on the 5th nymphal instar of Dericorys albidula (Orth.: Dericorythidae) (2006).
In this study, the effect of various concentrations of conidia of M. anisopliae var. acridum on different nymphal instars of D. albidula was assayed under laboratory conditions over two years. This was the first study of the efficacy of a fungal insecticide on D. albidula. The results indicate that M. anisopliae var. acridum affects the 2nd, 3rd, 4th, and 5th nymphal instars of this important pest of saxaul plants. In our study, the susceptibility of D. albidula nymphs was assessed over 2 yr using similar concentrations. The susceptibility of nymphs was greater in the second year (2006) than in the first year (2005). Unlike our study, Peng et al. (2008) researched the effect of M. anisopliae var. acridum against oriental migratory locusts, Locusta migratoria manilensis (Meyen) over two years (2002 and 2003) and reported that mortality rates caused by this fungus on the aforementioned locust was relatively similar in both years. In this study, the conidia of M. anisopliae were diluted in gasoline and results of this method were evaluated well. Using petroleum products had been tested previously. de Faria et al. (2002) showed that conidia of M. anisopliae var. acridum in a mixture of soybean oil and kerosene had a good effect on the locust, Rhammatocerus schistocercoides Rehn. Because saxaul plants are not used for food, using petroleum products can be a suitable method of control. In the current study, mortality was recorded after 15 d. Similar to our results Lomer et al. (1997) stated that M. anisopliae killed over 90% of nymphs after 15 d. These similar results indicate that 15 d is an adequate period for the fungus to take effect. Lomer et al. found that a dose 1010 of M. anisopliae var. acridum killed 100% of second instar nymphs of D. albidula. Magalhaes et al. (2000) stated that a 2 x 1013 concentration of M. anisopliae var. acridum caused 88% mortality on the 2nd nymphal instar of R. schistocercoides. As well, Alves et al. (1999) observed that M. anisopliae caused 79-90% mortality of short-horned locust in Africa, Brazil, and Australia. Kassa et al. (2004) examined the effect of Green muscle on Locusta migratoria (R. & F.) and reported that this compound can be effective on this pest.
In conclusion, the results of this study indicate that fungal insecticide M. anisopliae var. acridum diluted in gasoline was highly effective in causing mortality of 2nd, 3rd, 4th, and 5th nymphal instars of locust D. albidula in 2005 and 2006. As well, the current report shows that mortality of all stages in the second year (2006) was higher than in the first (2005).
We thank the Agricultural and Natural Resources Research Center of Qom, Iran, for its assistance.
Adeli, A., and M. Abaei. 1989. Study of harmful pests of saxaul plants of Iran. Annual report of research project. Environmental Research Studies Center, University of Tehran, Tehran, Iran. [ Links ]
Alves, R.T., R.P Bateman, C. Prior, and S.R. Leather. 1999. Effects of simulated solar radation on conidial germination of Metarhizium anisopliae indifferent formulation. Crop Protection 17:675-679. [ Links ]
Bateman, R.P 1997. Methods of application of microbial pesticide formulations for the control of locusts and grasshoppers. Memoires Entomology Society Canada 171:69-81. [ Links ]
Bischoff, J.F., S.A. Rehner, and R.A. Humber. 2009. A multilocus phylogeny of the Metarhizium anisopliae lineage. Mycologia 101:512-530. [ Links ]
Burges, H.D., and H.W. Hussey. 1971. Microbial control of insects and mites. Academic Press, London, UK. [ Links ]
de Faria, M.R., B.P. Magalhaes, R.T. Alves, F.G.V. Schmidt, J.B.T. da Silva, and H. Frazao. 2002. Effect of two dosages of Metarhizium anisopliae var. acridum against Rhammatocerus schistocercoides Rehn. Pesquisa Agropecuaria Brasileira 37:1531-1539. [ Links ]
Driver, F., R.J. Milner, and J.H.W. Trueman. 2000. A taxonomic revision of Metarhizium based on a phylogenetic analysis of ribosomal DNA sequence data. Mycological Research 104:115131. [ Links ]
Hunter, D.M., R.J. Milner, and P.A. Spurgin. 2001. Aerial treatment of the Australian plague locust, Chortoicetes terinifera (Orthoptera: Acrididae) with Metarhizium anisopliae (Deuteromycotina: Hyphomycetes). Bulletin of Entomological Research 91:93-99. [ Links ]
Kassa, A., D. Stephan, S. Vidal, and G. Zimmermann. 2004. Laboratory and field evaluation of different formulations of Metarhizium anisopliae var. acridum submerged spores and aerial conidia for the control of locusts and grasshoppers. BioControl 49:63-81. [ Links ]
Lacey, L.A., A.A. Kirk, L. Millar, G. Mercadier, and C. Vidal. 1999. Ovicidal and larvicidal activity of conidia and blastospores of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) against Bemisia argentifolii (Homoptera: Aleyrodidae) with a description of a bioassay system allowing prolonged survival of control insects. Biocontrol Science Technology 9:9-18. [ Links ]
Langewald, J., C. Kooyman, O.K.D. Kpindou, C.J. Lomer, A.O. Dahmoud, and H.O. Mohammed. 1997. Field treatment of Desert Locust (Schistocerca gregaria Forskal) hoppers in the field in Mauritania with an oil formulation of the entomopathogenic fungus Metarhizium flavoviride. Biocontrol Science and Technology 7:603-611. [ Links ]
Lomer, C.J., C. Prior, and C. Kooyman. 1997. Development of Metarhizium spp. for the control of grasshoppers and locusts. Memoirs of the Entomological Society of Canada 171:265-286. [ Links ]
Magalhaes, B.P., Q.M. Leco, M.R. Faria, F.G.V. Schmidt, and W.D. Guerra. 2000. Field trial with the entomopathogenic fungus Metarhizium anisopliae var. acridum against bands of the grass hopper Rhammatocerus Schistocercoides in Brazil. Biocontrol Science and Technology 10:427-441. [ Links ]
Moniri, V.R. 1998. Comparison of effect of chemical, microbial and hormonal compositions against Dericorys albidula in Isfahan province of Iran. p. 68. Final report of research project, Research Institute of Forest and Rangelands, Tehran, Iran. [ Links ]
Moniri, V.R., R. Omid, E. Farashiani, E. Azizkhani, and A. Salahi. 2005. Determination of best time to control of nymphs of the saxual locust, Dericorys albidula using hormonal insecticides (IGR). Journal of Research Institute of Forest and Rangelands of Iran 3:57-68. [ Links ]
Moore, D., and C. Prior. 1993. The potential of mycoinsecticides. Biocontrol News and Information 14:31-40. [ Links ]
Peng, G., Z. Wang, Y. Yin, D. Zeng, and Y. Xia. 2008. Field trials of Metarhizium anisopliae var. acridum (Ascomycota: Hypocreales) against oriental migratory locusts, Locusta migratoria manilensis (Meyen) in Northern China. Crop Protection 27:1244-1250. [ Links ]
Prior, C. 1992. Discovery and characterisation of fungal pathogens for locust and grasshopper control. p. 159-180. In Lomer, C.J., and C. Prior (eds.) Biological control of locusts and grasshoppers. CAB International, Wallingford, UK. [ Links ]
Quesada-Moraga, E., R. Santos-Quiros, P. Valverde-Garcia, and C. Santiago-Alvarez. 2004. Virulence, horizontal transmission, and sublethal reproductive effects of Metarhizium anisopliae (anamorphic fungi) on the German cockroach (Blattodea: Blattellidae). Journal of Invertebrate Pathology 87:51-58. [ Links ]
Rombach, M.C., R.A. Humber, and H.C. Evans. 1987. Metarhizium album, a fungal pathogen of leaf hoppers plant hoppers of rice. Transactions of the British Mycological Society 88:451-459. [ Links ]
Rombach, M.C., R.A. Humber, and D.W. Roberts. 1986. Metarhizium flavoviride var. minus var. nov., a pathogen of plant and leaf hoppers on rice in the Philippines and Solomon Islands. Mycotaxon 27:87-92. [ Links ]
SAS Institute. 1997. SAS/STAT. Guide for personal computers. Ver. 6.12. SAS Institute, Cary, North Carolina, USA. [ Links ]
Starnes, R.L., C.L. Liu, and P.G. Marrone. 1993. History, use and future of microbial insecticides. American Entomologist 39:8391. [ Links ]
Symmon, P. 1992. Strategies to combat the desert locust. Crop Protection 11:25-28. [ Links ]
Thomas, M.B., J. Klass, and S. Blanford. 2000. The year of the locust. Pest Outlook 11:192-195. [ Links ]
USDA. 2010. Field study using Metarhizium acridum, a mycoinsecticide for control of grasshoppers. Environmental Assessment December 2010. USDA, Plant Protection and Quarantine Animal and Plant Health Inspection Service, Riverdale, Maryland, USA. [ Links ]
Whitten, M.J., and J.G. Oakeshott. 1991. Opportunities for modern biotechnology in control of insect pests and weeds, with special reference to developing countries. FAO Plant Protection Bulletin 39:155-181. [ Links ]
Received: 22 March 2011.
Accepted: 5 July 2011