Background: The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a notorious polyphagous pest that has recently invaded India in 2018. Within a short period, this pest has spread throughout the country, causing a significant damage to maize. In order to manage this menace, farmers rely on chemical insecticides, but due to concealed feeding nature of this pest insecticides remain ineffective in reaching the target site. In this context, the present study aimed to isolate, characterize and evaluate the reproductive potential of the native strains of entomopathogenic nematode, Heterorhabditis indica against larval instars of S. frugiperda under laboratory conditions. Results: Two strains of H. indica isolated and characterized from the rhizosphere of mango and curry leaf trees were designated as CICR-HI-MN and CICR-HI-CL, respectively. Both strains, CICR-HI-CL and CICR-HI-MN showed differential mortality against 3rd (LC₅₀ value of 21.65, 48.91 IJs/larva), 4th (LC₅₀ value of 25.46, 52.36 IJs/larva) and 5th (LC₅₀ value of 59.20, 71.04 IJs/larva) instar larvae of S. frugiperda, respectively. The instar-wise mortality of S. frugiperda showed that 3rd instar was relatively more susceptible compared to 4th and 5th instar larvae. In terms of efficacy, CICR-HI-CL was almost twice effective than CICR-HI-MN when LC₅₀ and LC₉₅ values of 3rd instar larvae were compared. However, the reproductive potential of both the strains was significantly higher against 5th instar than the 3rd and 4th instar larvae. Strain CICR-HI-CL was more effective in larval mortality, while nematode reproduction was higher in CICR-HI-MN. Conclusions: Native strains of H. indica evaluated in the present study were found effective against larval instars of fall armyworm, S. frugiperda. Higher reproduction on 5th instar larvae demonstrates the ability of these strains to multiply, sustain and perpetuate on late instars of this polyphagous pest and may serve as viable option in integrated pest management program.

Exudation of mucilage from pinhead-sized boreholes in cocoa pods was recorded in Karnataka, India, during 2021. Further investigations showed the association of scolytine beetles with infested pods. The identity of the pest, Xylosandrus crassiusculus, was confirmed through morphological characterization and sequencing of the mitochondrial COI gene. We studied the predisposing factors for its infestation, visible and concealed damaging symptoms, and fungal symbionts. In addition to its well-known symbiotic fungus, Ambrosiella roeperi, a new association of yeast, Ambrosiozyma monospora, was discovered. We also traced the possible role of the mirid bug, Helopeltis theivora, in host selection by X. crassiusculus. Overall results indicated that a ‘mirid bug-ambrosia beetle–pathogen complex’ is responsible for the severe damage to cocoa pods in South India.

Globally Helicoverpa armigera, a polyphagous pest of many economic crops, has developed resistance to almost all groups of insecticides presently in used for its control. In cotton, its larvae cause severe damage and feeds on all plant parts including young leaves, square, flowers and bolls which in turn cause economic damage. Recent reports on development of its resistance to transgenic cotton which has Cry1Ac and Cry2Ab (Bt cotton) has given an indication of future threat to cotton growers. Therefore, use of semiochemicals as management strategy for these insects would be a great alternative as ethological pest management within insect pest management (IPM) to control this menace. These semiochemicals/volatile organic compounds can be present in insect (egg, larva, female) as well as in the host plant. In the present study, a total of seven volatiles have been identified from methanol extract of eggs and faecal pellets, out of which two volatiles; methyl ester of octadecanoic acid (methyl stearate) and methyl ester of hexadecanoic acid (methyl palmatate), were detected in egg samples. From faecal pellets five volatiles were identified namely octadecanoic acid (stearic acid) and its methyl ester, hexadecanoic acid (palmitic acid) and its methyl ester, tetradecanoic acid (myristic acid), caryophyllene and its oxide, phytol. Interestingly, methyl ester of octadecanoic acid and methyl ester of hexadecanoic acid were detected in both the samples. Volatiles observed in common may be used as effective semiochemicals in ethological pest management of Helicoverpa armigera. However, further study is needed to validate the competency of these fatty acids under field conditions.