Locusts are large invertebrates, short horned herbivores insects. The locust swarm existing now-a- days in Pakistan is of migratory type of species with scientific name “Locusta migratoria.

By : Ghous Muhammad, Dr. Muhammad Tahir

They belong to family acrididae and the order orthoptera. A locust plague species has two phases one is solitary and the other is gregarious. Solitary phase is the normal state of the species and the gregarious phase being a physiological response to violent fluctuations in the environment. When a nymph of a solitary-phase locust matures in the presence of many other locusts, it undergoes a physiological change and produces offspring of the gregarious type.

             Locusts are a serious threat to agriculture as they attack all kinds of crops and plants and a locust plague is a highly damaging natural catastrophe. These attacks have been alarmed and reversed the agriculture throughout the history. Pakistan is an agro-based country with a 62 and 23 percent people and national income is related to agriculture respectively. The most important threat now-a-days to agriculture is locust attack. The locust attack is similar in family, order and structure to the grass hopper. The locust has also been mentioned in the Holy-Quran in the surah Al-Aaraf. Locusts are natives of the deserts of Africa and after travelling long distance reached Saudi-Arabia via Red sea and after crossing Iran reach Pakistan in Baluchistan area of Tharparkar and Cholistan.

            Locust usually spend their breeding periods in the desert where the female can lay eggs up to 150 at a time inside a tube which they hide in the sand which protect it from predators. First, appear in coastal line from Karachi to the Iranian border in February and March. As temperatures rises, locust adults will start appearing in the interior of Baluchistan from Turbat to Dalbandin and Nushki, including Panjgur and Kharan villages. Locusts may also appear in the Huge Sandy Desert west of Kharan. Desert Locusts rarely move to the Chagai Hills and Quetta when they appear in the swarms form. Cold weather can delay locust egg hatching and maturation by several weeks or more. The breeding areas continue into adjacent coastal and interior desert areas of Iran (Sistan-Baluchistan province). Breeding periods in Baluchistan varies from yearly depending upon the timing, location and duration of the seasonal rains. In most years, spring rains will end in about April but ecological and egg laying conditions may remain favorable until June. In other years, insufficient rains fall to allow breeding and maturation stage-top a lower extent. The locust swarm attack heavily after every ten years in Pakistan and this year this attack is more swear due to the non-control effort by the Saudi-Arabia and Yemen war. Locusts are appealed to greenery and can eat flourishing fields of Cotton and Rice in just seconds but if you want to control them then they can only be controlled in deserts.

            A typical locust swarm can cover several hundred square kilometers. Locusts can fly up to two kilometers in the air and have even been reported to travel over whole oceans. It can comprise tens of millions of locusts, each eating their own weight in food every day.

            The Department of Plant Protection (DPP) at the Ministry of National Food Security & Research is maintaining the Desert Locust survey and control operations in Pakistan. DPP is situated in Karachi. Monitoring and Ground surveys are carried out regularly in the summer and spring intervals to check breeding areas from June to November and February to May, respectively. Surveys and monitoring guidelines are usually organized from permanent locust outposts (district offices) in the summer (Bahawalpur, R. Khan, Sukkur, Mirpurkhas) and spring (Pasni, Turbat, Panjgur, Kharan, Nushki) areas. During emergencies, seasonal outposts are established in the affected areas. During the attack season, a monthly meeting is held by the Indian and Pakistan monitoring agencies for locust monitoring from India and Pakistan to exchange information on the current locust situation in the area.

            In Pakistan it is a prominent threat and has spread like a virus in more than 17 districts in Punjab province. Now increasing the temperature is another dangerous threat because in hot environment their eggs will be hatched and their population will rise manifold. In the recent report, the Food and Agriculture Organization (FAO) of the united nation has warned of a huge level locust invasion in Pakistan if it is not controlled effectively it could cause potential threat because locust breeding is taking place at 38 percent of the country total area supported by suitable weather. It is reported that locust attack could 817 billion rupees loss to Pakistan agriculture production in 2020 which would turn unbearable to its insubstantial economy. So according to the present situation it is very necessary to adopt the preventive and control measures and strategies by the farmers and must being helped by the government.

            The best strategy to manage them is prevention. This means monitoring of locust habitats during dangerous periods of their lifecycle to detect the infestations early and allow quick reaction. Control operations can then be carried out before weighty increase of locust numbers and when there is no instant threat to cropping areas. For the time being, locust control operations are mostly carried out with chemical pesticides. Locust control staff is trained to carry out these operations with a view to avoid or control their negative effect on human health and the environment. Increasingly, low risk insecticides are used in locust control, such as insect growth regulators and result, effective locust control becomes more environments friendly.

            In management strategies there is a typically focus on creating exclusion zones – by burning tyres and by making noise by drum or any other steel pots to create an exclusion zone, catching through nets or digging trenches. At best, these local measures can prevent locusts from reaching a specific area and can do little to halt the progress of the swarm.

            Currently, the most commonly used control is insecticide.  Sprayed from land or aerial vehicles, whole swarms can be battered in relatively short periods of time. However, this has obviously led to some environmental concerns.

            Perhaps more effective method is biological control mechanisms. Natural predators such as wasps, birds and reptiles may prove effective at keeping small swarms at bay. However, for managing more established swarms, newly-developed targeted microbial bio pesticides, such as the fungus-base “Green Muscle”, offer a larger-scale solution.

            However, one of the most effective ways to avoid the overwhelming effects of locust plagues is to prevent them from happening in the first place. Considerable resources are allocated to early warning and preventative control strategies.  Locust monitoring stations collect data on weather, ecological conditions and locust numbers, making forecasts of the timing and location of breeding.

            Controlling locust swarms is no easy task. And the larger the swarms, the more tough the task becomes. Prevention, then, is likely the best medicine, but this requires keeping a very keen eye out. Remember, it only takes three locusts to make a swarm.

Ghous Muhammad, Dr. Muhammad Tahir
Associate Professo
Department of Agronomy
University of Agriculture Faisalabad