Climate Change Consultant
kalain.hosein@guardian.co.tt
According to the Old Testament of the Holy Bible, locusts were the eighth plague after God sent a series of ten plagues to pressure the Pharaoh to release enslaved Israelites.
For those in southern and eastern Trinidad, this biblical nightmare has become a near-annual reality for the last decade. Farmers and residents alike, from Icacos to Plum Mitan, now brace for these swarming creatures, no more than a few inches long, which bring their communities to a halt and cause tens of thousands in damage.
Their expanding footprint across Trinidad is due to changes in land use and, according to experts, a changing climate.
Understanding
Trinidad’s locusts
According to Nadia Ramtahal-Singh, an agricultural entomologist from the Ministry of Agriculture, Land and Fisheries, these grasshoppers, colloquially called locusts, have been recognised as pests in Trinidad since 1918.
Ramtahal-Singh explained that these pests are “migratory and gregarious, so they move in swarms,” which are characteristics of locusts. Hence, the terminology has been used interchangeably for these two species. There are two dominant species, the smaller Moruga Grasshopper (or “Moruga Locust”) and the larger Cedros Grasshopper (or “Cedros Locust”), both named after their place of origin.
Increasing locust outbreaks
While the Cedros Locust tends to remain in Trinidad’s far southwest, the Moruga Locusts have been migrating further and further away along and from Trinidad’s south coasts and have been the focus of research at the Ministry of Agriculture.
Historically, outbreaks of the Moruga Locust were reported every 14 years, but as of 2010, swarms have been reported nearly annually. Earlier in 2024, Guardian Media visited Barrackpore, where residents said they were grappling with the infestation of the Moruga Locust that had inundated their homes, vehicles, and vegetation. When Guardian Media visited the community, Julien Trace was stained with the remnants of thousands of dead hoppers, crushed under the weight of passing cars.
Resident Paul Rooplal said this was the first time the hoppers had hatched in Plananite Trace, recounting, “For three days now, the baby grasshoppers have hatched. They are consuming everything, and we cannot even open our doors. We have to close up when cooking.”
Another resident, Indra Balgobin, said she has been relentlessly spraying to kill the pests: “I spend a lot of time with my plants; it’s so sad to see how they eat them. I don’t know what to do. I called the (agriculture) office, but no one came. The woman I called said they could not do anything, but I think they should come and spray.”
Since 2014, according to agricultural entomologist Ramtahal-Singh, who has been conducting research on the Moruga Locusts, reports of these pests have spanned as far as 47 kilometres northeast of Moruga into Plum Mitan, just over half the length of Trinidad from the south coast.
Based on reports collected by the Ministry of Agriculture, there are four distinct clusters where these swarms occur—southwestern Trinidad from Siparia to Icacos (a mix of the Cedros and Moruga Locusts), with the Moruga Locusts dominating in south-central Trinidad from Morrne Diablo to Debe, Moruga to Tabaquite, and Rio Claro to Plum Mitan further east.
Climate change’s role
According to the Ministry of Agriculture, their behaviour has changed to allow them to migrate over long distances, but their behaviour is only one of the culprits. Ramtahal-Singh explained that the top three reasons are climate change, which leads to changes in how T&T experiences rainfall and temperatures, and human encroachment into and near forested areas. “We believe the difference between the dry and wet seasons is affecting the life cycle, and they’re moving out of areas they are accustomed to being okay,” Ramtahal-Singh explained.
Climate change can be blamed for a host of impacts on our environment, but Ramtahal-Singh elaborated that the changed climate has also led to changes in the life cycle. Between July and September, they are typically immature adults called nymphs or hoppers and begin to move. By October, they reach maturity and begin to meet, leading to copulation.
These locusts generally survive one year and produce one generation, and once they mate, they die after eggs are laid. However, by December, according to Ramtahal-Singh, “If the rains come, the hatching of the eggs will be delayed, and it will begin in January.” She added that the locusts will not fly in heavy rains, which can also quell swarms from migrating far across the island in wetter months, but it provides ideal breeding conditions.
In the latest update of climate normals from the Trinidad and Tobago Meteorological Service, every month of the year now has a lower average rainfall accumulation when the averages are compared from 1981-2010 and 1991-2020. According to projections from the Intergovernmental Panel on Climate Change, the tropics are expected to become progressively drier in a warmer world.
Still, when showers, thunderstorms, and tropical cyclones form in our region, they are likely to be more intense, causing local extreme rainfall totals. Based on data from the Trinidad and Tobago Meteorological Service, Trinidad and Tobago has been warming at a rate of 0.24˚C per decade since 1946, with the last two decades being the hottest on record.
In T&T, every single year since 1986, the temperature has been warmer than the 1961-1991 climatological average. These creatures can eat or exist in a variety of temperature ranges, but their digestion is much more specific. Locusts can fill their stomachs faster than they can digest food. Recent studies have shown that locusts can assimilate far more energy in future climates than current climates, between eight and 17 per cent more energy per wet season than currently, proportional to how much warmer it is.
The Ministry of Agriculture also said there are 20 traditional locust egg beds in south Trinidad, averaging approximately 10,000 feet. However, more egg beds are cropping up in non-traditional areas due to forest clearance. They also added that locust bands in T&T are merging rather than remaining in separate bands while the infestations are spreading in non-traditional areas because of forest clearance.
Trinidad’s management strategies
The Ministry of Agriculture said they work alongside key stakeholders, including the public, for sighting reports, and they can spring into action, tracking the locusts’ flight paths and locating their eggs. Once the eggs are located, officials use an “integrated pest management” (IPM) strategy.
The “chemical management strategy” is currently ongoing, chiefly using two chemicals. Ramtahal-Singh explained that the ministry sprays Propoxur, also known as Baygon, and Ethrine Plus, also known as Cypermethrin. “Part of the IPM strategy is that we do monitoring and surveillance.
The locusts tend to go back to where they hatched, and the egg beds are. We monitor and survey the areas where we are accustomed to seeing them. Once the hatching begins, we start the chemical control,” Ramtahal-Singh said.
She touted the programme’s success so far, but she highlighted the caveat that they are only able to reach the locusts that exit in the forested areas or at the edge of forest reserves. “We manage within some areas and farming communities, but the ones that are deep within the forest, we are unable to access them,” she added.
She also cautioned those who would like to see spraying everywhere: “Propoxur is an insecticide that kills everything—including beneficial insects.” Research shows it is also highly toxic to many birds and honeybees and moderately to slightly toxic to fish and other aquatic species.
A new, safe, nature-based solution
As a result, Ramtahal-Singh said the ministry was now trying to use a “biological control agent” to make the environment safer for all flora, fauna, livestock, and humans. “We started research back in 2022 on this biological control agent, metarhizium acridum, an entomopathogenic fungi, which is being manufactured in other countries to control locusts, specifically desert locusts.”
She explained that the Ministry of Agriculture imported it, and laboratory trials began at the Research Division in Centeno in 2022 and 2023. Ramtahal-Singh added, “We tested NOVACRID, an active ingredient from the metarhizium acridium, against adults and first stages. We had 100 per cent mortality within eight days of the laboratory trial, so we knew it was a success.”
At the beginning of 2024, the Ministry of Agriculture conducted a field trial using NOVACRID between January and March in Princes Town and Penal. According to Ramtahal-Singh, 100 per cent mortality within five days was specific to locusts and grasshoppers.
This story was produced as part of Internews’ Earth Journalism Network’s Reporting Fellowship.