This study aimed to gather information about farmers’ knowledge, perception and management practices of the newly introduced insect pest, the fall armyworm Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Manica province, Mozambique. A total of 200 smallholder farmers with experience in maize cultivation were surveyed using a semi-structured questionnaire. The survey was conducted between May and August 2019 in four districts: Macate, Manica, Sussundenga and Vanduzi. Most farmers were unable to morphologically identify fall armyworm (FAW) (from 93.9% in Vanduzi to 98.0% in Manica). Most farmers have experienced FAW damage in their farms (from 92% in Macate to 98.0% in Manica). Maize is mostly planted in October and November (from 44.0% in Sussundenga to 60.0% of farmers in Manica), but the highest infestation period is believed to be between November and February. With the exception of Vanduzi where 65.3% of farmers apply insecticides, most farmers in other districts do not use any method to control FAW (from 60.8% in Macate to 88.0% in Manica and Sussundenga respectively). Among those applying insecticides, from 65.0% in Manica to 75.0% in Vanduzi have confidence in the efficiency of the insecticides being used against FAW. Most farmers reported an increase in the spread of FAW. The lack of financial resources is reported as the main constraint in the fight against FAW. This study is the first of its nature in the province of Manica and provides valuable information that may support extension services and researchers when designing FAW management options for local smallholder farmers.

Attack symptoms, constraints, morphological identification, pest management, smallholder farmers

The fall armyworm Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is a polyphagous insect pest originating from the Americas, where it has more than 350 different host plants including both crop and non-crop species (Montezano et al. 2018). Despite its ability to survive in different host plants, fall armyworm (FAW) is known to have a high preference for maize (Molina-Ochoa et al. 2001; Nagoshi et al. 2018). In Africa, FAW was first reported in West and Central Africa in 2016 (Goergen et al. 2016) and rapidly spread to the rest of the continent with devastating consequences on maize production (Feldmann et al. 2019).

The larval stage of FAW consists of six instars. Young larvae usually feed on leaves creating windows and moistened sawdust-like frass near the funnel and upper leaves. During daylight, young larvae hide in the funnel, becoming active during the night. Older larvae stay in the funnel where they are protected from insecticide application and natural enemies, making it difficult to control them (Prasanna et al. 2018). Development rate is affected by diet (Abrahams et al. 2017) and temperature (Early et al. 2018). FAW populations can expand rapidly in tropical areas, where warmer temperatures allow more generations per year (Assefa and Ayalew 2019). At an average temperature of 28 °C, the life cycle of FAW is completed in around 30 days but can be extended in cooler temperatures (Prasanna et al. 2018).

In Mozambique, FAW was confirmed in early 2017 (Cugala et al. 2017). In 2018, FAW was also reported in Asia (Sharanabasappa et al. 2018). The rapid spread of FAW is largely attributed to its migratory potential (Meagher et al. 2004) and high dispersal capacity (Kumela et al. 2018). The problem of FAW in sub-Saharan Africa is exacerbated because its preferred host plant, maize, is a staple food in the region (Midega et al. 2018; Prasanna et al. 2018; Harrison et al. 2019). In Mozambique, for example, 21 to 90% of households depend on maize for daily consumption (MASA 2016). In 2017, it was estimated that by 2018, FAW would have caused an economic loss of around US$ 3 billion in Africa (Abrahams et al. 2017). In the absence of proper control methods, FAW has the potential to cause huge yield losses (Prasanna et al. 2018) as was reported in Mozambique where a year after its detection, around 49 thousand tons of maize were reported to be lost as a direct consequence of FAW attack (FAO 2018).

Farmers have various forms of indigenous knowledge to tackle pest problems, but such knowledge is often neglected (Mendesil et al. 2007). Surveys designed to ascertain farmers’ knowledge and practices regarding pest management are important because they can highlight the need for the training of farmers in the identification of pests and the debunking of pest management misconceptions (Arshad et al. 2009). Crop losses due to insect pests may be prevented, or reduced, by deploying effective crop protection measures, which to a large extent depend on farmers’ knowledge and behaviour towards pest management (Midega et al. 2016; Kansiime et al. 2019).

For effective deployment of control methods for a given pest, farmers should be able to morphologically identify the target pest and distinguish it from non-target organisms. In cases of economically important and invasive insect pests such as FAW, it is crucial to know how familiar farmers are with the pest, what options they have to control it and what their main constraints are. Understanding these factors is critically important for setting a research agenda, designing extension strategies, and formulating research that meets farmers’ demands (Arshad et al. 2009; Mendesil et al. 2016; Kumela et al. 2018). To respond to these concerns, this study was designed to provide baseline information that can be used by extension services and research institutions in determining how the problem of FAW should be addressed at the smallholder farmers’ level. This study aimed to assess the knowledge, perception and management practices of FAW among smallholder farmers of the central province of Manica, Mozambique.

Traditionally, the head of the household in the area of study is a man. But specific circumstances may compel women to take on this role, such as when they are divorced, widowed or single. The educational background of farmers seems to play a major role in their ability to get alternative/additional jobs. Given that most farmers rely solely on agriculture, it is both a means of subsistence and a source of income. Although in this study no relationship was established between the level of education and knowledge of FAW, Abtew et al. (2016), pointed out the importance of education in farmers’ level of knowledge of agricultural pests. Given that the majority of farmers in the present study have primary education or are illiterate, that may well explain their lack of knowledge of the FAW. Although farmers may own 3 ha or more of land, one should note that not all the area is under cultivation. Due to their limited income, farmers prefer to use their stored maize seeds from the previous harvest, as certified seeds are seen as expensive.

Invasive alien species represent a serious challenge in the context of pest management because farmers and local agricultural extension workers rarely know about the presence of a newly arrived and spreading species until disastrous damage occurs (Toepfer et al. 2019). In Mozambique, for example, FAW was initially confused with stem borers by agricultural extension workers (Cugala et al. 2017). A similar scenario was also reported in Nigeria where FAW was also confused with indigenous species of Spodoptera (Goergen et al. 2016). Although most farmers in Zambia (91%) (Kansiime et al. 2019) and in Ethiopia (99%) and Kenya (100%) (Kumela et al. 2018) could positively identify FAW larvae through its morphological characteristics, the same could not be observed in the present study, as only a maximum of 6.1% of the farmers could identify FAW larvae. That might be explained by the fact that the majority of farmers (from 71.4% in Vanduzi to 94.0% in Macate and Susundenga) did not receive any training in identification of FAW. It is important to point out that at the time of the study, the extension service workers themselves were under training in identification and control of FAW by the Ministry of Agriculture, FAO and other agriculture related organizations and universities. Because FAW is a new pest, it can be easily confused with other caterpillars, especially those belonging to the same family (FAO and CABI 2019). However, Toepfer et al. (2019) underscored the fact that even if farmers are not trained by extension workers in identification and management of FAW, they will learn, over time, through their own experiences with the new pest.

The infestation of FAW in maize fields is reported to be high between November and February. This can be explained by the fact that in this interval, maize planted from October to December is still in the vegetative stage which is the most preferred by FAW. But a field survey conducted from May to August 2019 and between December 2019 and January 2020 in the same area, found that FAW infestation was higher during the dry season (Caniço et al. 2020).

Despite an official recommendation from the government to use a select range of insecticides composed of 23 different active ingredients belonging to the major groups of pyrethroids, organophosphates carbamates and organoclorades, and highly selective pesticides such as Spinosad, Beauveria bassiana and Bacillus thuringiensis to fight FAW (Cugala et al. 2017), only about 12.0% in Macate and Sussundenga, 40.0% in Manica and 65.3% in Vanduzi appeared to follow the recommendation. Abate et al. (2000), explained that although local extension services in African countries may encourage the use of pesticides for pest management, most smallholder farmers rely on indigenous approaches when dealing with pests such as crop associations, mechanical control, use of herbal products and, sometimes, in supernatural ways. Concerning the specific case of FAW in Africa, several methods of control of the pest were reported in various countries such as Zambia where farmers use chemical, cultural and biological control (Kansiime et al. 2019), Ethiopia and Kenya where among other methods, farmers use physical and traditional methods (Kumela et al. 2018). In Zimbabwe for example, as reported by Chimweta et al. (2020), most of the farmers applied pesticides recommended by the government to control FAW, although some of them used non-conventional materials such as washing powders, indicating lack of knowledge of the pest and its methods of control.

In this study, in contrast to other countries, chemical control was the only method used by a limited number of smallholder farmers. Because of the importance of the pest and, with the objective of widening available options, African researchers are testing alternative methods of monitoring and control of FAW, such as the push-pull technology tested in Kenya, Tanzania and Uganda with promising results (Midega et al. 2018) and pheromone trap design and lures for monitoring FAW tested in Togo (Meagher Jr et al. 2019). Because insecticides in Africa are mostly used improperly and often traded in dubious markets, it was recommended that the management of FAW should be based on biopesticides such as the fungi Beauveria bassiana and Metarhizium anisopliae and baculoviruses because they are environmentally safe with a low risk of human intoxication (Feldmann et al. 2019). Bacillus thuringiensis, a bacteria-based biopesticide, could also play a role in low-cost methods (Hruska 2019). Furthermore, when biopesticides are combined with good crop management, they can keep pest levels under control (Bateman et al. 2018).

In this study, there was a common belief among farmers from all districts that FAW is rapidly spreading. This behavior of the pest has been predicted in Zimbabwe by Chimweta et al. (2020) and a similar trend was also observed in Ethiopia and Kenya by Kumela et al. (2018). When farmers were asked about their major constraints in the fight against FAW, some reported no constraint while most of them (from 52.0% in Macate to 74.0% in Sussundenga) indicated the lack of financial means to support the acquisition and application of insecticides, combined with the inefficiency of insecticides being used (from 6.0% in Sussundenga to 18.0% in Macate). In Zimbabwe, around 84.1% of the farmers also reported the lack of financial resources as the main constraint, followed by 73.2% who indicated inadequate labor as the main constraint (Chimweta et al. 2020). A similar scenario was reported in Ethiopia, where the major problems affecting FAW management efforts were reported to be lack of adequate knowledge of the pest and its management options, combined with scarcity of financial and material resources (Assefa and Ayalew 2019). Depending on the context, smallholder farmers may have limitations that will define their pest management options (Hruska 2019).

Although farmers are aware of the presence of FAW in maize fields, the majority of them are unable to morphologically distinguish FAW from other caterpillars, which probably affects their ability to control the pest. Despite there being a government list of recommended pesticides to be used in the fight against FAW, a small proportion of farmers apply insecticides while the majority of farmers take no measure against the pest. Nevertheless, most farmers believe that the incidence of FAW in their fields is high and that the pest is spreading to other territories. Given the importance of FAW to food security, educational campaigns addressing the issues of identification and control of the pest should be implemented targeting smallholder farmers. Alternative methods of control of FAW should be investigated as the simple recommendation of insecticides or other methods that are perceived as expensive or hard to implement may not work.

The authors wish to acknowledge the assistance of Maria Madinga, Nelson Alferes, Tendai Pita, Milagre Patrocínio, Nicolau José and Isolta Cadeado from Instituto Superior Politécnico de Manica in conducting the survey. We also thank Márcio Adamo from Instituto Superior Politécnico de Manica for the production of the map of the sampling locations and the farmers and agricultural services of each district for their collaboration.

This study was financially supported by FCT-Fundação para a Ciência e a Tecnologia, I.P., through the project UID/AGR/04129/2020 (LEAF) and a PhD scholarship (SFRH/BD/135260/2017) under the PGCD program – Programa de Pós-Graduação Ciência para o Desenvolvimento in Portugal.