The ‘Sena’ Caterpillar invasion: Where are we heading?

By PROF. ROHAN RAJAPAKSE

Emeritus Professor of Entomology, University of Ruhuna

This is a continuation of the previous article written by me, published in The Island on 19 Jan 2021. (Fall Armyworm: Strategies for Effective Management). I also wrote about this pest in 2019 and I have emphasised the following: The Fall armyworm – FAW (Spodoptera frugiperda known as sena caterpillar) female is a strong flier capable of flying more than 100 KMs per day, nearly 500Km of flying during lifetime, depositing 1500 eggs an average. The other factors that are centered on FAW are: FAW consumes many different crops but prefers Maize; also it spreads quickly across large geographical areas, and can persist throughout the year.

The FAW, originated in the Americas, invaded the Africans in 2016, and was detected in the Indian subcontinent, in 2017, and believe the FAW naturally migrated to Sri Lanka, from India, in 2018. Sri Lanka lost the initial opportunity in 2018, as we were not adequately prepared to stop the spread, although the Department of Agriculture did some work; but the FAW was present in all SL districts, except Nuwara-Eliya and Jaffna. The ban on cultivating maize, in the following year helped to contain the spread, but now it is spreading again, confirming the belief that once FAW invaded it will stay.

Hence what are the strategies available now? As we emphasized, the management of FAW has to be centered on Short, Mid and Long-term strategies.

Short-Term Strategies:

Destruction of FAW eggs found on leaves and developing whorl by hand. The middle level expertise in the Department, such as Agricultural Instructors, KVS and the development and Project Assistants, recently recruited to the Government service, along with the farmers, should be trained to detect the eggs and destroy them immediately on the ground. If we miss this opportunity, the eggs will mature and tiny first instars larvae could be seen. At this stage, the only opportunity is to apply a Department of Agriculture approved chemical pesticide, using a knapsack sprayer or power sprayer at the recommended dilution. The names of the recommended pesticides are available with all research and extension officers of the Department of Agriculture.

It is also recommended that no single strategy of FAW pest control will yield strategic results. The employment of Integrated Pest Management Strategies should be carried out, such as combining Chemical control with cultural and sanitary control practices, which will give satisfactory control. When the larvae are small, proper timing and spray of pesticides are critical for elimination of this pest.

Mid-Term Strategies

: It is of paramount importance to understand that elimination of these dangerous pests are to be carried out jointly by the Government and Provincial Councils for effective control. The US University researchers, after working jointly with USDA, have identified the effective parasitoids, and they have released millions of parasitoids using the federal government facilities and the Universities in Florida, Georgia, and South Carolina.

Sri Lanka should avail this opportunity by writing to the authorities of the USDA, and arranging to import the strategic parasitoids, already identified to suit tropical countries, such as Sri Lanka.

This reminds me of the imports of eggs. Larval and pupal parasitoids from Indonesia, Malaysia, and establishment of those parasitoids in the WP and Coconut Research Institute to eliminate the Coconut leaf boring caterpillar Promecotheca cumingii n early and mid -70s in Western Province, which is in practical operative till now.

Long-Term Strategies:

Sri Lanka should declare an Emergency if it wants to eleminate the pest. Maize is a staple food of many African countries. The Long-term strategies are early detection of the pest, stopping its spread, and initiation of research programmers to import tolerant varieties, and granting permission to import such tolerant varieties produced by SEEDS giants, such as Monsanto.

However, these could be controversial. The Director General of Agriculture should be the leader and chief executive of this strategy, and no one should undermine his authority, as we witnessed a team of Rwandan experts, from Ghana, coming here and advising farmers without the knowledge of the DG, and even the Minister himself. Still no one knows what sort of pesticidesethese Rwandan Experts have recommended?

(The writer is Former Senior Professor of Agriculture Biology, University of Ruhuna. Received his PhD in Entomology from the University of Florida, USA, in 1985, on a research assistantship. The title of this thesis is on the Fall armyworm, its parasitoids and Ecology for effective management)