Fundamental and Applied Agriculture Vol. 5(3), pp. 295–302: 2020 doi: 10.5455/faa.123992 PLANT PROTECTION j PERSPECTIVE ARTICLE Early preparedness: Bangladesh proactive steps towards desert locust invasion in South Asia Mohammad Shaef Ullah 1*, Dilruba Sharmin1,2, Malvika Chaudhary 3 1Laboratory of Applied Entomology and Acarology, Department of Entomology, Bangladesh Agricultural University, Mymensingh, Bangladesh 2National Pest management Expert, Food and Agriculture Organization of the United Nations (FAO), Dhaka, Bangladesh 3Asia Regional Coordinator - Plantwise, CABI, New Delhi 110012, India ARTICLE INFORMATION ABSTRACT Article History The desert locust Schistocerca gregaria (Forskål) is considered as the most Submitted: 10 Aug 2020 devastating transboundary pest of all migratory pest species in the world Accepted: 13 Aug 2020 due to its high reproduction rate, ability to migrate long distances, and de- First online: 14 Aug 2020 struct the crops. The ongoing spread of desert locusts in the region of South Asia represents an unprecedented threat to food security and livelihoods. Although there are many factors involved, change in climate directs unpre- dictable direction to wind which is responsible for this unusual spread of Academic Editor pest from India towards Nepal. According to the Food and Agriculture A K M Mominul Islam Organization of the United Nations (FAO), even before the cyclone Amphan [email protected] hit the country, dry conditions prevailing in the west forced immature adult swarms to move eastward in India, crossing the entire northern India as far as Bihar and Orissa. Though the risk posed by desert locust is extremely low *Corresponding Author in Bangladesh, the chances get much lower because of the monsoon. During Mohammad Shaef Ullah the monsoon it gets very humid and the potential of nymphs getting infected [email protected] by pathogens is high and they die naturally being completely outside of their desert habitat. The rapid and sudden upsurge of the locust population that is unleashing destruction globally can be attributed to aberrant and erratic climatic behaviour triggered by global warming. Therefore, the government of Bangladesh is taking proactive steps to manage different trans-boundary pests to ensure food security and livelihoods. Keywords: Desert locust, trans-boundary pest, invasion, wind, food security, South Asia Cite this article: Ullah MS, Sharmin D, Chaudhary M. 2020. Early preparedness: Bangladesh proactive steps towards desert locust invasion in South Asia. Fundamental and Applied Agriculture 5(3): 295–302. doi: 10.5455/faa.123992 LL LOCUSTS are grasshoppers, but only Acrididae in the world (Latchininsky, 2013; Pratha- a few grasshoppers are locusts. Gener- pan, 2020). Locusts have been considered as the en- ally, locusts are a kind of short-horned emies of humans since the beginning of agriculture grasshoppers (Suborder: Caelifera; Fam- (Arthur, 2008). Sometimes locust swarms brought Aily: Acrididae) of the insect order Orthoptera (Cap- devastation and caused famine to entire nations. Lo- inera, 2008). They are known to exhibit their density custs live in the “solitary phase” characterized by dependent behavioral, physiological, and phenotypic camouflage coloration, in frequent social interactions, polymorphism (Song, 2011). Only about 18 species and sedentary behavior under low population densi- of large grasshoppers, which exhibit pronounced be- ties. On the contrary, locusts develop into the “gregar- havioral and/or morphological differences between ious phase” often with strikingly black-and-orange phases, should be considered as locusts among the colored nymphs, which march in cohesive “hopper 6,400 described grasshopper species of the family bands” at high densities (Cullen et al., 2010, 2017; Ma Ullah et al. Fundam Appl Agric 5(3): 295–302, 2020 296 et al., 2011; Song, 2011; Ott et al., 2011). Damaged area caused by desert locust Desert lo- The desert locust Schistocerca gregaria (Forskål, cust is extremely polyphagous. They can attack more 1775) are known to change their behavior and form than 500 plant species and includes all kinds of agri- swarms of adults or bands of hoppers (wingless cultural crops. An adult desert locust can consume nymphs). This swarms can be dense and highly mo- fresh food of roughly its own weight per day, which bile. The desert locust outbreak affected 8 million approximately weighs about two grams every day. A people in more than 20 countries with an estimated 80 1 km2 size swarm contains about 40 million desert to 100% of crop lost in 2003–2005, mostly sub-Saharan locusts eat the same amount of food in one day as Africa (Brader et al., 2006; Latchininsky, 2013). Desert about 35,000 people (Cressman, 2016). This is based locust damage can most convincingly be compared on eating an average of 2.3 kg of food per day by a to a natural disaster like a hurricane or a tornado. person, according to the USDA. Life cycle and dispersing capacity of desert locust Ecology of the locust Desert locust increases in Desert locusts are notorious due to their high fecun- numbers when the conditions are favorable for re- dity and reproduction rates (Lazar et al., 2016). Desert production and numbers decrease either by natural locust females lay eggs primarily in sandy soils at a mortality or through migration when the conditions depth of 10-15 cm below the surface in an egg pod are adverse (Fig. 2). Most favorable conditions for (Symmons and Cressman, 2001)(Fig. 1). A solitary breeding of the desert locust are (1) moist sandy or female lays higher eggs i.e. about 95-158 eggs in a sand/clay soil to depths of 10-15 cm below the sur- pod, whereas a gregarious female lays fewer eggs face, (2) some bare areas for egg-laying, and (3) green i.e. 80 eggs in a pod. Females locust can lay eggs at vegetation for hopper development. Seasonal rains least three times usually at an interval of about 6-11 in the deserts trigger the growth of green vegetation, days in their lifetime. Generally, up to 1,000 egg pods which attracts the desert locusts (Cressman, 2016). have been found in one square meter (FAO, 2020). This species is extremely sensitive to changes its den- The life cycle of locust includes a succession of three sity, and phase transformation occurs very frequently stages: egg, nymph, and adult. Although the life cy- and rapidly. Females often form cluster to lay eggs, cle of desert locust is extremely variable and depends which starts and/or lead to the gregarization. They mostly on weather and ecological condition, a desert exist in different conditions known as recessions (with locust lives a total of about three to five months (Sym- low and intermediate numbers), rising to outbreaks, mons and Cressman, 2016). The life cycle comprises and extremely high densities or plagues (Magor et al., the duration of three stages as follows: 2008). Desert locust plagues started, spread and de- • Hatching of eggs is about two weeks (the range clined long before application of effective pesticides is 10-65 days) and suitable methods existed (Rainey et al., 1979; Trat- alos et al., 2010). Three factors are playing a role in • Development of hoppers in five to six stages ending plagues of desert locust. They are (i) Insuffi- over a period of about 30-40 days, and cient rainfall, (ii) Movement of swarms to areas un- suitable for breeding and survival, and (iii) Control • Maturity of adults took place in about three efforts - predominantly based on chemical methods. weeks to nine months (mostly from two to four months). Affected countries by the desert locust During Depending on the wind, desert locusts usually fly quiet periods (known as recessions) desert locusts are at a speed of about 16-19 km h−1. In a day, swarms of usually restricted to the semi-arid and arid deserts desert locust can travel about 5-130 km or more (Ped- of Africa, the Near East and South-West Asia that gley, 1981). Adult locusts can stay in the air for long receive less than 200 mm of rain annually (Dinku periods of time. For example, desert locusts cross the et al., 2010). This is an area of about 16 million square Red Sea regularly, a distance of 300 km. This group kilometers, comprising of about 30 countries (Fig. 3). of desert locust travels a long way during daytime Desert locusts may spread over a massive area of destructing the crops and take rest at night. Desert some 29 million km2 during plagues and extending locust swarms can vary from less than one square over or into parts of 60 countries (Latchininsky, 2013). kilometer to several hundred square kilometers. At This is more than 20% of the total land surface of the least 40 million and sometimes as many as 80 mil- world. The desert locust has the potential to damage lion locust adults can be accommodate in each square the livelihood of a tenth of the world’s population kilometer of swarm. It was reported that a swarm during plagues (FAO, 2020). that invaded Kenya covered an area of 200 km2 in early 1954. The predictable density was 50 million individuals km−2 giving an entire number of 10 bil- The desert locust invasion in south Asia Though lion locusts in that swarm (Rainey et al., 1979; Rainey, the desert locust upsurge remains critical in East 1989; COPR, 1982). Africa, Yemen and Southwest Asia has become vul- Ullah et al. Fundam Appl Agric 5(3): 295–302, 2020 297 Eggs Depth: 5-15 cm Laying period: 7-30 hrs Female lay: 2-3 times Laying interval: 6-11 days Eggs/pod: 60-150 egg Egg/female: 140-400 eggs Incubation period: 10-65 days Mating 1st instar 2nd instar Nymph (Solitary) Adult Instars: 5-6 Colour: Swarming Colour: Green/greenish Immature: Pink Dev.