*3.3. Cropping Practices*

Two main cropping systems were used for maize production: single-cropping in rotation with other crops (cotton, cowpea, cassava, soybean, and groundnut) and intercropping with cassava, groundnut, cowpea, and sorghum. Overall, single-cropping was the most common cropping system (67.6%) (Table 5). More than half of the farmers applied mineral fertilizers to the maize plants, on average 134.6 kg/ha of NPK (Nitrogen, Phosphorus, and Potassium) and 75.4 kg/ha of urea.


**Table 5.** Farmers' cropping practices.

Traditional varieties refer to local varieties cultivated by farmers over generations while modern varieties refer to improved varieties developed by research centers. About 58.7% of the farmers grew traditional varieties of maize (Table 5). Farmers who grew modern varieties of maize used more mineral fertilizers and intercropping. In addition, farmers who grew traditional varieties of maize used fewer mineral fertilizers and practised more single-cropping in rotation with other crops.

#### *3.4. Damage Caused by S. frugiperda*

The results showed that around 97.1% of farmers su ffered from *S. frugiperda* attacks in 2018. It confirms the presence of *S. frugiperda* throughout Benin, despite the geo-climatic contrasts (Table 1). About 93.9% of the maize fields were infested. The incidence of damaged maize plants per field was estimated to 58.9%, and the incidence of damaged maize ears was estimated at 50.4%. The estimated yield losses by farmers averaged 797.2 kg/ha of maize in 2018 (Table 6). The farmers revealed that before the invasion of *S. frugiperda*, they obtained an average maize yield of 1626 kg/ha. Thus, the yield losses caused by *S. frugiperda* represented 49% of the average maize yield that farmers obtained before the invasion of *S. frugiperda*.


**Table 6.** Indicators of damage caused by *S. frugiperda* according to farmers.

The analysis of the severity of *S. frugiperda* attacks was carried out by distinguishing the different parts of the attacked maize plants, in particular the leaves and ears. The majority of farmers reported that *S. frugiperda* attacks were moderately severe on the leaves and ears (Table 6). At the time of the attack, they found large elongated perforations on the leaves, whorl attack and damage ranging from 15 to 25% of maize grains.

Chi-square tests showed that there was a relationship between the severity of *S. frugiperda* attack and the types of grown maize varieties. The severity of *S. frugiperda* attack on the leaves and ears was significantly associated with types of grown maize varieties (*p* = 0.001). *S. frugiperda* attacks were more severe for modern varieties of maize. There was no significant relationship between the cropping systems, application of mineral fertilizers, and attack severity (Table 7).


**Table 7.** Chi-square test analysis of the relationship between cropping practices and the severity of *S. frugiperda* damage.

DF: Degree of Freedom; χ2: Chi-square value; *p*: Probability; \*\*: *p* < 0.01, ns: not significant.

#### *3.5. Knowledge of Natural Enemies, Host and Repellent Plants of S. frugiperda*

About 16% of farmers stated knowing insects and birds that feed on *S. frugiperda* larvae. They identified the francolin (*Francolinus bicalcaratus*), the village weaver (*Ploceus cucullatus*), and the common wasp (*Vespula vulgaris*) as natural enemies of *S. frugiperda*. For 14% of farmers, *S. frugiperda* could destroy other crops besides maize. They said the pest could damage sorghum, cotton, cowpea, and tomato crops.

In addition, about 5% of farmers stated knowing plants that repel *S. frugiperda*. They identified yellow nutsedge (*Cyperus esculentus*), chan (*Hyptis suaveolens*), shea tree (*Vitellaria paradoxa*), neem (*Azadirachta indica*), tamarind (*Tamarindus indica*), and soybean (*Glycine max*) as repellent plants of *S. frugiperda*.

#### *3.6. Farmers' Management Practices*

About 38% of the farmers surveyed used at least one control practice. The most common managemen<sup>t</sup> method used by farmers was synthetic pesticides. Among farmers using at least one managemen<sup>t</sup> method, 91.4% used synthetic pesticides, 1.9% used botanical pesticides, and 6.6% used other managemen<sup>t</sup> practices. The wide range of synthetic pesticides used by farmers included Thalis 112 EC (emamectin benzoate and acetamiprid), Pyro FTE 472 (cypermethrin and chlorpyriphos-ethyl), Pacha 25 EC (lambda-cyhalothrin and acetamiprid), Lambda super 2.5 EC (lambda-cyhalothrin), and Emacot 019 EC (emamectin benzoate) (Table 8).


**Table 8.** Management practices used by farmers.

The average e ffectiveness score for all of these synthetic pesticides is 5 out of 7. Thus, farmers believed that synthetic pesticides were relatively e ffective against *S. frugiperda*. Among the synthetic pesticides, Emacot 019 EC is the one for which the average e ffectiveness score is 6 followed by Thalis 112 EC whose score is 5 (Table 8).

The botanical pesticides used by farmers against *S. frugiperda* were usually made from neem leaves or seeds (*Azadirachta indica*), vernonia leaves (*Vernonia amygdalina*), pepper (*Capsicum annuum*), and ashes. Some farmers also added other raw materials such as soap, detergents, or petroleum to botanical pesticides. The average e ffectiveness score for all botanical pesticides is 6 and indicates that the botanical pesticides were e ffective against *S. frugiperda*.

Moreover, some farmers used other practices to manage *S. frugiperda* (7%). These included early planting, handpicking larvae, and the application of ash to the whorls of maize. The average effectiveness score for these practices is 3 and indicates that they were relatively ine ffective against *S. frugiperda*.

Chi-square tests showed that there was a relationship between knowledge of the pest and the use of managemen<sup>t</sup> practices (*p* = 0.001) and between knowledge of the pest and the types of managemen<sup>t</sup> practices used (*p* = 0.002) (Table 9). This result confirms that the implementation of managemen<sup>t</sup> strategies by farmers was associated with their knowledge of the pest. The Chi-square tests also showed that the use of managemen<sup>t</sup> practices by farmers and the type of managemen<sup>t</sup> practices used were significantly associated with membership in a farmer organization and contact with research or extension services (Table 9).


**Table 9.** Chi-square test analysis of the relationships between farmers' managemen<sup>t</sup> practices, knowledge, perceptions, and socio-economic characteristics.

DF: Degree of Freedom; χ2: Chi-square coefficient; *p*: Probability; \*: *p* < 0.05, \*\*: *p* < 0.01, ns: not significant.
