Temperature 34 C New Delhi, IN
Sunday, July 05, 2020
No Image

Two locust look-alike grasshoppers cause public panic

G.K. Mahapatro1 and Gavas Ragesh*

 1ICAR – Indian Agricultural Research Institute Regional Station, Pune, Maharashtra

*Banana Research Station, Kerala Agricultural University, Kannara, Thrissur, Kerala

The Year 2020 commenced with COVID-19 pandemic followed by slew of news on the intrusion of large swarms of desert locusts into India, unleashing public panic amid large scale desert locust control campaigns by governmental agencies. With a second wave of locusts forecasted by FAO during July 2020, some states of India are on a high alert to effectively manage this invasion after a gap of 26 years since last large locust invasion. Meanwhile reports of sporadic outbreak of the locust like two grasshoppers were observed in different parts of our country especially from South East and North East India during the lockdown period.

In an article published (12-June, Down To Earth) highlighting preemptive actions planned by the Bihar agriculture department over possible locust attack, the inadvertently placed photo of spotted grasshopper attracts our scientific attention and intervention.  This has caused confusion to the readers; this grasshopper attack was already reported from various parts of our country.

In another faux pas, it was misquoted that swarm of locusts normally travel during night hours (11 pm to 4 am) and fly in the morning. Which is in contrary to the facts mentioned by us in our earlier publications (Lockdown, Locusts and Laudable Lessons, 1-June; and Warning locust warrants no panic, 11-June) both in Smart AgriPost. The latest Desert Locust Situation Bulletin (No.11, period 1-15 June), don’t show any locust invasion in Bihar.

Two short horned grasshoppers look-alike locust that caught public awe and attention are actually not locust but spotted coffee grasshopper (Aularches miliaris), and Aak grasshopper (Poekilocerus pictus); both under the same family Pyrgomorphidae.

The foaming from body – first hand identification clue to farmers for spotted grasshopper

Aak grasshopper are large brightly colored grasshopper, exhibiting warning coloration, nymphs are notorious for squirting a jet of liquid to long distances when disturbed and grasped.

Desert Locust (Schistocerca gregaria)

As the name indicates, they show characteristic polyphenism, behavioral and morphological changes coupled with serotonin secretion associated with phase transformation in locust formation. In their solitary phase (solitaria morph) early instars are cryptic greenish while older adults are greyish. The solitary phase grasshoppers lack black patterning as present in the gregarious (or gregaria morph) phase where the body is pinkish in early instars and bright yellow in adults.

The inability of desert locust adults to eject bitter defensive secretion from thorax in response to disturbance as seen in other two grasshoppers is the clear-cut clue for public and farmers in differentiating them from other two grasshoppers. This point should be given due attention, that needs no insect taxonomist even for dispelling the doubts amid public.

FAO has long-standing expertise in monitoring Desert Locust populations and cooperating affected countries to cope with this international pest. FAO issues Desert Locust Bulletin every month by Desert Locust Information Service (DLIS). DLIS continuously monitors the global Desert Locust situation, weather and ecology to provide early warning based on survey and control results from affected countries combined with remote sensing, historical data and models. It advises on details of preemptive actions undertaken by member countries in preventing locust spread. The bulletin is supplemented by alerts and continual updates during desert locust activities. The general public and agencies involved with locust management activities can assess relevant information (inclusive identification of locust) through FAO portal www.fao.org/ag/locusts.

Spotted coffee and Aak grasshoppers should not be confused with locust.  Desert locust is true pestiferous trans-boundary pest with migratory nature. A clear understanding on these grasshoppers will help us in avoiding unnecessary panics and wastage of public funds in managing those insect pests that never warrants international assisted monitoring and preventive strategies, like required in locust.

(Author can be reached by emails: gagan_gk@rediffmail.com  and/or  gavash.ragesh@kau.in for feedback and comments. Opinions are their personal.)

 

(Please share your experience, interesting news articles and case studies at smartagripost@gmail.com)