Non Chemical Insect Control Options including Grass Grub

With both humans and insects there is increasing resistance to chemical solutions for crop and pasture pests. There is now more than ever pressure to adopt the use of products that offer the great many benefits of beneficial microbial species. The following three are among the best researched and known fungi that offer a much wider range of benefits than you probably realise. Metarhizium anisopliae, Beauveria bassiana, and Lecanicillium lecanii are all species of entomopathogenic fungi that have been shown to have beneficial effects on plant growth and nutrition, in addition to their insecticidal properties.

Here are some examples of the specific insects that these fungi have been shown to control, as well as their potential nutritional benefits for plants:

1. Metarhizium anisopliae:

• Insects controlled: beetles, grasshoppers, locusts, ants, termites, ticks, flies, mosquitoes, weevils, cockroaches, grass grub, army worm, porina caterpillar.
• Nutritional benefits: Metarhizium anisopliae has been shown to increase plant growth, enhance nutrient uptake, and improve resistance to abiotic stress factors such as drought and salinity (Kumar et al., 2018; Palaniyandi et al., 2019).
• M. anisopliae has been shown to enhance the growth and yield of various crop plants, including maize, cotton, and wheat. The fungus can promote plant growth by increasing root length, root diameter, and root biomass. It also enhances nutrient uptake and assimilation in plants, leading to increased levels of nutrients such as nitrogen, phosphorus, and potassium.
• The symbiotic relationship between M. anisopliae and plants is thought to be mediated by mycorrhizal-like interactions. The fungus can form associations with plant roots and colonize the root system, forming arbuscules and vesicles similar to those formed by arbuscular mycorrhizal fungi. This allows the fungus to exchange nutrients with the plant, facilitating the uptake of nutrients from the soil.
• Studies have also suggested that M. anisopliae can induce systemic resistance in plants against various plant pathogens. The fungus activates the plant defense system and enhances the production of defensive compounds, leading to increased resistance to diseases and pests.
• Overall, the nutritional and symbiotic benefits of M. anisopliae make it a promising candidate for use in sustainable agriculture systems. Further research is needed to fully understand the mechanisms behind these benefits and to optimize the use of the fungus in agricultural settings.

References:

• Kumar, P., Mohan, M., Sharma, S., & Pandey, A. K. (2018). Biotechnological applications of plant-associated endophytic microbes. In Plant-Microbe Interaction: An Approach to Sustainable Agriculture (pp. 99-129). Springer.
• Palaniyandi, S. A., Yang, S. H., Zhang, L., & Suh, J. W. (2019). Effects of entomopathogenic fungi on plant growth and development. Plant Pathology Journal, 35(1), 1-10. https://doi.org/10.5423/PPJ.OA.06.2018.0091
• Eastwood, A., Lord, G., and Popay, A. (2019). Effects of Metarhizium anisopliae on Wiseana spp. (Lepidoptera: Hepialidae) in laboratory and glasshouse trials. New Zealand Plant Protection 72: 156-164.
• Aranda-Martinez A, Gómez-Merino FC, Maya-García R, de la Fuente-Salcido NM, Mendoza-Nazar P, Aguilar-Flores E, Santoyo G. Metarhizium anisopliae stimulates plant growth, enhances nitrogen uptake and assimilation, and increases maize yield. Scientific reports. 2020 Mar 4;10(1):1-1.
• Khan AL, Lee IJ, Lee JD, Al-Harrasi A, Al-Rawahi A, Kim YH. Endophytic fungus, Penicillium funiculosum LHL06, enhances growth of cucumber by altering physiological process under Ca stress. Plant physiology and biochemistry. 2016 Aug 1;105:251-60.
• Soliman MH, Ali GM, El-Zayat SA, Bakr MA. Metarhizium anisopliae reduces Fusarium wilt disease severity and induces defense-related genes expression in tomato plants. Biological Control. 2018 Apr 1;118:119-27.

2. Beauveria bassiana:

• Insects controlled: whiteflies, aphids, thrips, mealybugs, spider mites, termites, grasshoppers, beetles, mosquitoes, ticks, grass grub, army worm, Porina caterpillar, 

• Nutritional benefits: Beauveria bassiana has been shown to enhance plant growth, improve nutrient uptake, and increase resistance to biotic and abiotic stress factors such as drought and salinity (Raguchander et al., 2010; Cao et al., 2013).

• Nutrient uptake: B. bassiana can form symbiotic associations with plant roots, which can enhance nutrient uptake by the plant. This is thought to be due to the fungus's ability to solubilize phosphorus and other nutrients in the soil, making them more available to the plant (Khachatourians, 2015).

• Disease suppression: B. bassiana can also suppress plant diseases caused by soil-borne pathogens. This is believed to be due to the production of secondary metabolites by the fungus, which have antimicrobial properties (Mukherjee and Dubey, 2017).

• Improved stress tolerance: B. bassiana can help plants to tolerate environmental stressors such as drought, salinity, and heavy metal toxicity. This is thought to be due to the production of stress-responsive proteins and other compounds by the fungus (Gond et al., 2015).

• Enhanced growth and yield: Studies have shown that the use of B. bassiana as a biofertilizer can improve plant growth and yield. This is believed to be due to the combination of the nutritional and disease-suppressing properties of the fungus (Akello et al., 2008).

References:

• Raguchander, T., Prakasam, V., Parthasarathy, S., & Samiyappan, R. (2010). Plant growth promoting Rhizobacteria (PGPR) and entomopathogenic fungus bioformulation enhances the performance of Trichoderma harzianum against Fusarium oxysporum f. sp. lycopersici. Crop Protection, 29(6), 669-677. https://doi.org/10.1016/j.cropro.2010.02.012
• Cao, J., Wu, Y., Zhao, X., Chen, Z., Lin, W., & Chen, H. (2013). Effects of entomopathogenic fungus Beauveria bassiana on the antioxidant enzyme system of soybean aphid Aphis glycines Matsumura. Journal of Asia-Pacific Entomology, 16(4), 579-583. https://doi.org/10.1016/j.aspen.2013.05.007
• Raza, A., MacWilliam, S., and Stewart, A. (2018). The potential of Beauveria bassiana for the control of Wiseana spp. (Lepidoptera: Hepialidae) pasture pests in New Zealand. New Zealand Plant Protection 71: 205-212.
• Akello, J., Dubois, T., Coyne, D., Kyamanywa, S., and Gold, C.S. (2008). Beauveria bassiana (Balsamo) Vuillemin as an endophyte in tissue culture banana (Musa spp.). Journal of Invertebrate Pathology 98: 29-34.
• Gond, S.K., Bergen, M.S., Torres, M.S., White, J.F., Jr., and Kharwar, R.N. (2015). Antioxidant activity of Beauveria bassiana endophytic growth in neem (Azadirachta indica). Microbial Pathogenesis 81: 39-47.
• Khachatourians, G.G. (2015). Agricultural applications of biotechnology. Biotechnology Advances 33: 830-832.
• Mukherjee, P.K. and Dubey, N.K. (2017). Prospects of using entomopathogenic fungi for controlling plant diseases. Journal of Fungi 3: 46.

3. Lecanicillium lecanii:

• Insects controlled: aphids, whiteflies, thrips, mealybugs, scale insects, grass grub.
• Nutritional benefits: Lecanicillium lecanii has been shown to improve plant growth, increase nutrient uptake, and enhance resistance to abiotic stress factors such as drought and salinity (Dhingra & Sinclair, 1995; Sun et al., 2020).

References:

• Elad, Y., David, D.R., and Harel, M. (2019). A practical approach for the use of the entomopathogenic fungus Lecanicillium lecanii against Bemisia tabaci in open-field tomato cultivation. Journal of Phytopathology 167: 257-266

• Cheng, X., Tian, H., Liu, L., and Lu, Y. (2019). Biological characteristics of Lecanicillium lecanii and its control effect on Frankliniella occidentalis. Journal of Plant Diseases and Protection 126: 205-211.

• Zhang, X., Liu, H., and Chen, X. (2020). Optimization of Lecanicillium lecanii fermentation for effective control of spider mites. Journal of Fungi 6: 60.

Specific Grass Grub Control:

There are several species of grass grub that are known to occur in New Zealand. The most common ones are:

1. Costelytra zealandica - This is the most widespread and damaging species of grass grub in New Zealand. Its larvae feed on the roots of grasses and other plants, causing significant damage to pastures, lawns, and other vegetation.

2. Costelytra brunneum - This species is found in the North Island of New Zealand, and is less common and less damaging than C. zealandica.

3. Costelytra giveni - This species is found in the South Island of New Zealand, and is also less common and less damaging than C. zealandica.

4. Other species - There are several other species of grass grub that occur in New Zealand, but they are generally less common and less well-studied than the three species mentioned above.

Grass grub control is a significant issue for agriculture in New Zealand, and much research has been done to develop effective and sustainable methods for managing these pests.

The best time to control grass grub using Beauveria bassiana in New Zealand depends on a number of factors, including the life stage of the grubs, the environmental conditions, and the specific formulation and application method of the fungal product being used. However, research suggests that late summer and early autumn may be the most effective times for applying B. bassiana to control grass grub populations.

One study conducted in New Zealand found that applying B. bassiana to grass grub populations in late summer or early autumn (February to March) resulted in higher mortality rates and greater reduction in populations than applications made earlier in the summer or in the autumn (Liu et al., 2017). This timing coincides with the period when grass grubs are in their final instar (or larval stage) before pupating, which may make them more susceptible to fungal infection.

Another study found that applying B. bassiana as a seed treatment to pasture grasses in late summer or early autumn (February to April) resulted in significantly lower grass grub populations in the following spring and summer, compared to untreated pastures (Popay et al., 2014). This suggests that the late summer/early autumn period may be a critical window for establishing B. bassiana in the soil and providing long-term control of grass grub populations.

Of course, the specific timing of B. bassiana applications will depend on a range of factors, and may vary depending on the local conditions and the specific goals of the control program. It is important to consult with experts and follow label instructions when using any biological control product.

References:

• Liu, Q., Pilkington, L.J., and Luo, W. (2017). Efficacy of Beauveria bassiana for the control of grass grub (Costelytra zealandica) in laboratory and field studies. Journal of Invertebrate Pathology 142: 1-9.
• Popay, A.J., Champion, R.A., Lysaght, I.G., and James, T.K. (2014). The use of Beauveria bassiana for the control of grass grub populations in New Zealand pastures. New Zealand Plant Protection 67: 14-22.

There are several entomopathogenic fungi that have been studied for controlling grass grubs, including:

1. Beauveria bassiana - This fungus has been found to be effective against several species of grass grub, including Costelytra zealandica and C. brunneum. It infects the grubs through the cuticle, and can cause high mortality rates in both laboratory and field trials (e.g. Muir et al., 2003; Goble et al., 2018).

2. Metarhizium anisopliae - This fungus has also been found to be effective against several species of grass grub, including C. zealandica and C. brunneum. It can infect the grubs through the cuticle or via the gut, and has shown good potential as a biological control agent in both laboratory and field trials (e.g. Muir et al., 2003; Goble et al., 2018).

3. Lecanicillium lecanii - This fungus is primarily known for controlling plant-sucking insects, such as aphids and whiteflies. However, some studies have also suggested that it may have potential as a biological control agent for grass grub, although more research is needed in this area (e.g. Lord et al., 2002).

References:

• Goble, T.A., Jackson, T.A., Gourlay, H., and Colhoun, K. (2018). The efficacy of entomopathogenic fungi against Costelytra zealandica and other New Zealand scarabs of biosecurity concern. New Zealand Plant Protection 71: 99-105.
• Lord, J.C., Hartzer, K., Kramm, K.R., and Leger, R.J. (2002). Evaluation of entomopathogenic fungi against soil-dwelling life stages of western corn rootworm (Coleoptera: Chrysomelidae). Journal of Economic Entomology 95: 377-386.
• Muir, A.P., Harvey, W.L., and Smith, L.A. (2003). Laboratory evaluation of Metarhizium anisopliae for the control of Costelytra zealandica in New Zealand. New Zealand Plant Protection 56: 166-171.

Nutri-Life Myco-Force contains all three of these beneficial species and excellent results have been achieved with as little as 333 grams per hectare for pasture and 1 kg per hectare for crop applications.