Prof. Latigo On Locusts: Uganda Barking The Wrong Tree

The locust issue for me has not been well handled with the scientific leadership that ought to define the best ways forward.

In such circumstance where we do not have firsthand experience to guide, you bring together the best scientists holding diverse views to present objective perception of the challenge, advance hypotheses, propose ways forward, and to subject each to critical and brutal scientific scrutiny.

Once the science is cleared, hypotheses set, and options for critical action defined, strategies to counter the challenge can then be developed with appropriate experts in monitoring, data gathering and analysis, procurement, transportation, deployment, and evaluation, and with critical communication channels and infrastructure put in place.

The truth of the matter is that the Desert Locusts are best controlled in their breeding sites when still young. These locusts mainly breed in deserts and prefer very sandy soils where they can easily penetrate and quickly lay their eggs before they are eaten by predators.

Reason why they are called Desert Locusts and why they breed mainly in desert or arid areas.

It does not surprise that some swarms reportedly turned back towards Karamoja as much of neighboring Acholi, Teso and Lango is currently covered in thick vegetation.

In the past, the Desert Locust Control Organization of Eastern Africa used to monitor locust breeding sites in arid areas of Kenya, Somalia etc. to assess the population of nymphs that emerge.

When nymphs are few, the locusts behave like ordinary grasshoppers and live individual or solitary lives, and they don’t swarm and are scattered all over.

But when nymphal densities are very high, the instinct to aggregate and move together, to become gregarious, is triggered in them.

They then crowd together and even become adults in dense populations. That is when they are easily spotted, sprayed and controlled.

If these nymphs are not destroyed at this stage, they will become adults living together in large numbers. These adults will have the same instinct of being together- they are gregarious,- and will feed and fly together.

In their large numbers, adult locusts feed voraciously and constantly face the risk of starvation and being easily spotted and eaten by predators. Therefore, their greatest urge is to move and mate constantly and quickly reproduce. This is what we see in the swarming and quick movements.

Once locusts are not prevented from swarming from their breeding sites, much of what we can do are matters of fate and chance, and largely ineffectual.

Thus, in our case now, it does not make sense to try and ambush the locusts anywhere and spray them: (1) Being largely blown by wind, we can never predict their movements so as to lay the said ambush; (2) the ground spraying teams, the 2000 UPDF soldiers, cannot spray the locusts in flight or spray the locusts that largely rest on shrubs and trees in the bushes where movement is virtually impossible; (3) the use of one or two drones is meaningless in such wide, diverse, thickly vegetated and unmapped areas of locust movement where effective drone use cannot be attained (as one needs knowledge of the terrain to program and effectively operate the drones); and (4) the greatest predators of locusts are birds, kites, hawks that fly. Locusts instinctively counter these predators by diving into the grass as many may have seen. So as drones fly towards locust swarms, the immediate instinct is for them to dive down or land on the nearest vegetation to diminish their exposure.

Even for those spraying on the ground, the immediate response of the locusts to their movements is dropping deep in the grass. This also reduces their exposure to any insecticides sprayed.

As a matter of fact, excessive and unnecessary activities may even help disperse the locusts to areas where they escape natural predators and will breed in low numbers and undetectable populations thus worsening the after effect of their invasion.

In the circumstance, what should be our best approach to dealing with the locust invasion?

(1) In areas potentially threatened by the locusts, all food crops still in the fields must be harvested before the locusts arrive. If there are no crops in the fields, they locusts pause no immediate arm and are just good for eating; (2) Where swarms are landing must be closely identified and mapped. After two weeks, nymphs will have emerged and are visible as they aggregate. Such nymphal populations remain vulnerable, because they only jump around and spread little until they become adults in 2-3 weeks. There is thus enough time for their presence to be reported, assessed and attacked by a spray team such as the UPDF has assembled but are now being wrongly and ineffectively deployed; (3) Local populations must be sensitized about the above facts and incorporated into the locust monitoring and control process.

Lastly, were our locust response strategies well thought out and will they work? My emphatic view is NO. Not at all.

Firstly, nothing that we are currently doing suggests that we recognized the reality that the anticipated locust invasion is largely a matter of chance and deeply dependent on unpredictable wind intensity and direction that, with weather changes, may not even occur at significant levels. If we did, we would never have deployed soldiers the way we did.

Secondly, there is no evidence in the current interventions that suggests that the above stated scientific facts about the locusts,  systematic response planning and  strategy development took place.

The silent complaint of my fellow entomologists that many of them from Makerere or NARO were never consulted would not have been there.

Instead, what we heard first from the Ministry of Agriculture was an urgent request for funds without any stated purpose; then the plan to deploy UPDF to intercept the locusts as they “invaded”; and later the deployment of hundreds of soldiers with knapsack sprayers in Karamoja that are totally ineffective against flying locusts or those roosting on trees and shrubs and in thickly vegetated terrains.

Thirdly, is, so far, the glaring mismatch between locust occurrences and deployment of control teams, with the locusts playing a costly and truly wasteful hide-and-seek game with the UPDF spray teams.

The cost of this unscientific and ineffective deployment as been the story that shs15 billion has already been spent and more money is now needed. To do what, only God knows.

Fourthly, in all the locust invasion districts of northern and eastern Uganda, virtually no crops, except cassava and sweet potatoes, are in the field.

Even if the locusts are left to spread out while being closely monitored to map their movements and identity their breeding grounds in order to target subsequent nymphs, no significant economic damage will be done to require current efforts.

In fact, since the primary focus of the locusts is mating and identification of suitable breeding grounds and multiplying rapidly therein, and given that we can only best suppress the locusts by targeting these sites and spraying the nymphs when they are most vulnerable, the pesticides and resources we are now wasting must be preserved to use against the subsequent nymphal generations of the invading locusts and not be wasted on the futile efforts to destroy the swarming and evasive adults.

And, while at it, we must accept the reality that our interventions must be based on good science and knowledge, and we must avoid empty posturing and cheap know-it-all stances that keep our experts at bay.

Most importantly, we must avoid lulling our people to the idea that the locust challenge will end with the invading swarms because the swarms are not the most harmful.

The real challenge is whether the locusts will disperse wide enough and breed in solitude that will prevent pinpoint spraying. This will allow the locusts to remain in their breeding areas to subsequently cause tremendous damage in the next season and beyond.

Of course, with rain and other adverse weather conditions, all these locusts worries could still come to nought. Whatever we do though, we must base ourselves on sound knowledge and not politics and power became locusts do no respond to them.

Prof. Morris Ogenga-Latigo

Prof. Latigo is MP Agago North/ Member Pan African Parliament and a leading Insect Ecologist. mwolatigo@gmail.com