1. Introduction
Pseudococcidae (Hemiptera: Coccomorpha) is a large family of mealybugs widespread across the globe in terms of species diversity (Yerlikaya et al., 2023). Historically, mealybugs were not considered major pests of cotton in India (Asia-Pacific Consortium on Agricultural Biotechnology, 2006). However, mealybugs (Pseudococcidae) have recently caused severe economic damage to Gossypium herbaceum and Musa paradisiaca, reducing yields by up to 40–50% in several areas of Kalakad in the Tirunelveli region (December 2023–May 2024). The unexpected occurrence of mealybugs in cotton and weed hosts presents new challenges in cotton cultivation and pest management. There is very limited information on this pest and its associated biotic factors. The present investigation, conducted from December 2023 to May 2024 in Gossypium herbaceum and Musa paradisiaca growing areas of the Kalakad region, Tirunelveli District, South Tamil Nadu, India, has yielded extensive data. The ladybird Cryptolaemus montrouzieri, a known predator, has demonstrated proven effectiveness in controlling mealybug pests (Golsteyn et al., 2021).
2. Materials and Methods
Intensive surveys were conducted in December 2023, during which samples were collected from the Kalakad region in Tirunelveli District, Tamil Nadu. The surveys involved examining the stems, leaves and other green parts of plants in these areas. The samples were collected to identify species belonging to the family Pseudococcidae, as well as predatory species from the family Coccinellidae, including mealybug destroyers, mealybug Leptomastix and parasitoids. The locations where each sample was collected were also documented.
2.1. Collection and Identification of Mealybug Species
Field-collected mealybugs from Gossypium plants were brought to the laboratory, preserved in 70% ethyl alcohol and mounted on slides. The specimens were identified using taxonomic keys and the repository collection of coccids kept in the Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore.
2.2. Collection and Identification of Alternate Hosts
Mealybug-infested weed plants in the banana and cotton ecosystems were also collected, and their identification was accomplished with the help of the agricultural officers in Kalakad.
2.3. Collection and Identification of Natural Enemies of the Mealybug in the Kalakad Region
2.3.1. Predators
Coccinellid predators collected from mealybug-infested cotton plants were identified using standard taxonomic keys to the common species of coccinellids.
2.3.2. Parasites
The field-collected mealybug species from banana plants were brought to the laboratory and kept in emergence cages (Bharathi & Muthukrishnan, 2017). The parasitoids emerged from the mealybug colonies at the LTD laboratory in Tiruchi.
3. Results and Discussion
Managing mealybug infestations presents significant challenges for farmers due to the high diversity of mealybug species and the necessity for precise identification and documentation before implementing control measures. Our research highlights the critical need for thorough species identification to effectively address mealybug problems. The study documented various mealybug species affecting Gossypium herbaceum and Musa paradisiaca in the Kalakad region of Tirunelveli District. Accurate identification is pivotal, as it enables targeted control strategies, ensuring that pest management practices are both efficient and environmentally sustainable. Without this detailed understanding, control measures may be less effective, leading to prolonged pest issues and potential economic losses for farmers.
Furthermore, the research underscores the importance of natural enemies in managing mealybug populations. By identifying and studying the predator species from the Coccinellidae family, including their interactions with mealybugs, the study supports the role of these natural enemies in pest control. The presence of effective biological control agents, such as the ladybird Cryptolaemus montrouzieri, can significantly enhance pest management efforts. This approach not only aids in controlling mealybug populations but also helps in maintaining the ecological balance within agro-ecological areas. Thus, integrating natural enemies into pest management strategies is crucial for sustainable agriculture, promoting both crop protection and environmental health.
| Sl. No. | Month (cropping period) | Standard week | Mealybug (Grade)* | No. of samples collected | % of predators | |||
|---|---|---|---|---|---|---|---|---|
| Cryptolaemus montrouzieri | Cryptolaemus montrouzieri larvae | Green lacewings | Ladybugs | |||||
| 1 | December 2–8 | 49 | 0 | 50 | 0 | 0 | 0 | 0 |
| 2 | December 9–15 | 50 | 0 | 50 | 0 | 0 | 0 | 0 |
| 3 | December 16–23 | 51 | 0 | 50 | 0 | 0 | 0 | 0 |
| 4 | December 24–31 | 52 | 0 | 50 | 0 | 0 | 0 | 0 |
| 5 | January 1–7 | 1 | 0 | 50 | 0 | 0 | 0 | 0 |
| 6 | January 8–14 | 2 | 0 | 50 | 0 | 0 | 0 | 0 |
| 7 | January 15–21 | 3 | 0 | 50 | 0 | 0 | 0 | 0 |
| 8 | January 22–28 | 4 | I | 50 | 0 | 0 | 0 | 0 |
| 9 | January 29– February 4 | 5 | II | 50 | 6 | 10 | 6 | 0 |
| 10 | February 5–11 | 6 | I | 50 | 16 | 18 | 0 | 8 |
| 11 | February 12–18 | 7 | I & II | 50 | 18 | 16 | 0 | 2 |
| 12 | February 19–25 | 8 | I & II | 50 | 10 | 0 | 10 | 0 |
*Note:
Grade 0 – No incidence
Grade I – Scattered appearance
Grade II – Full incidence on any one of the branches
References
- Asia-Pacific Consortium on Agricultural Biotechnology. (2006). Bt cotton in India: A status report.
- Bharathi, K., & Muthukrishnan, N. (2017). Survey and records of mealy bugs species on cotton and alternate host of key mealy bug Phenacoccus solenopsis Tinsley and its natural enemies complex in major cotton growing areas of South Tamil Nadu, India. International Journal of Current Microbiology and Applied Sciences, 6(12), 1047–1054. https://doi.org/10.20546/ijcmas.2017.612.118
- Golsteyn, L., Mertens, H., Audenaert, J., Verhoeven, R., Gobin, B., & De Clercq, P. (2021). Intraguild interactions between the mealybug predators Cryptolaemus montrouzieri and Chrysoperla carnea. Insects, 12(7), Article 655. https://doi.org/10.3390/insects12070655
- Yerlikaya, H., Başpınar, H., Uygun, N., & Kaydan, M. B. (2023). Mealybug (Hemiptera: Pseudococcidae) predators of the family Coccinellidae (Coleoptera) from Aydın Province, Türkiye. Türkiye Biyolojik Mücadele Dergisi, 14(1), 54–62. https://doi.org/10.31019/tbmd.1226047