FAW-Guard: “A Novel Microbial Consortium Solution for Fall Army Worm”

Introduction

Fall Army Worm (Spodoptera frugiperda (J E Smith), Lepidoptera: Noctuidae), is a difficult pest of major crops all over the world causing severe damage and yield loss which vary and depend on various factors, but can range from 19 to 100%. The control of fall armyworm has been based principally on the use of chemical insecticides. However, biological control is a highly desirable management alternative for controlling this pest in the long term. Entomopathogens including fungi, bacteria, virus, nematodes and protozoans play a very important role in natural regulation of fall armyworm populations in the field. Among the fungal entomopathogens, Metarhizium anisopliae and Beauveria bassiana are found to be effective against FAW. 

The R&D dept. of IPL Biologicals Limited has innovated a novel Consortia product namely, FAW-Guard, using the two effective entomopathogens i.e., Metarhizium anisopliae and Beauveria bassiana along with certain additives and metabolites, in a specialized formulation process. After rigorous lab testing and field studies of multiple formulations, FAW-Guard (formulation-23) was found effective in controlling the population of FAW. It is also eco-friendly in nature and also harmless to natural predators and parasites.

Benefits of the product

• It can control populations of fall armyworm (common names maize borer and Spodoptera frugiperda).  

• Single product provide benefit of two entomopathogens.    

• Eco-friendly and cost effective.

• Harmless to natural predator and parasites.

Mode of Actions

Beauveria bassiana

• Beauveria bassiana conidia infect the insect skin by penetrating and lysing (with enzymes) the epicuticle. Once inside the insect it grows and releases toxin called Beauvericin and Oosporin that weakens the host’s immune system. Eventually the entire body cavity is filled with fungal mass. Insects, before succumbing to fungal infection, exhibit various symptoms including restlessness, cessation of feeding and loss of coordination.

Metarhizium anisopliae 

• It infects all the stages of insects including eggs, larvae, pupal, nymphal and adults. When a spore (conidium) of M. anisopliae lands on the insect, it attaches to the insect's external cuticle via a germ tube. It germinates after 24-48h and then penetrates, using enzymes and mechanical force, through the insect cuticle (which is lipophilic) to the inside of the body cavity. Here it develops and reproduces in the insect, progressively digesting the body cavity. Approximately four to 10 days after infection, the insect dies. The insect body ultimately gets covered with green mycelium and spores, which may get dispersed and cause subsequent infections. Certain toxins called destruxin produced by this fungus also cause the mortality of insects.

Additives and Metabolites

• Additives in the form of organic compounds are added to improve the efficacy and process parameters are optimized to increase the metabolites synthesis and their composition in the final product.

Method of Application

Apply FAW-Guard @ 5 to 7.5ml/Lit of water as foliar spray in standing crop at the time of pest appearance. Follow 2-3 foliar spray in the morning time by using high volume spray to cover the entire standing crop. Repeat application at 7 days or 15 days interval or as required.

Bio-efficacy of FAW-Guard (Lab and Field studies) 

The Bio-efficacy of the novel consortia product FAW-Guard was tested in different lab and field studies. Dose response studies for the product was conducted in lab in which different stages of FAW was considered for mortality check. It was found to be effective against the 2nd and 3rd instar of FAW @ 5 to 7.5ml/Lit of water (Figure 1).

Figure 1: Laboratory bioassay of FAW-Guard against fall armyworm  

In-house Field Trial

Field trial of FAW-Guard was conducted during Kharif-2020 at Bijnor (U.P), India against FAW in Maize crop. Two dosages of FAW-Guard i.e., 1L/acre (or @5ml/L water) and 1.5L/acre (or @7.5ml/L water) was considered for comparison against the chemical Lambda cyhalothrin @ 500 ml/acre, 50% of FAW-Guard + 50% of  Chemical and Untreated control where only water was sprayed. 

Figure 2: Effect of FAW-Guard on FAW of Maize crop in field (7^th day after spray).

After 7 days of the spray 74% mortality of fall armyworm larvae was recorded in FAW-Guard @ 1.5 lit/acre which is at par chemical treatment Lambda cyhalothrin @ 500 ml (76%).  Similarly 65% mortality was recorded for FAW-Guard @1L/acre which is at par with the combination of 50% FAW-Guard + 50% Chemical (68%). Both the dosage of FAW-Guard were found effective in controlling the FAW population as compared to the untreated control (Figure 2 and Table 1).

Table 1: Effect of FAW-GUARD against fall armyworm in Maize crop after 7^th days of application

Conclusion

1. FAW-Guard is a novel microbial consortia which controls the population of destructive pest fall armyworm.

2. It is more effective as it contains combination of two different fungal entomo-pathogens.

3. It is beneficial over the chemical insecticides as it does not have any residual effect.

This article was initially published in AgroPages' '2021 Latin America Focus' magazine.