Efeito dos insecticidas botânicos no controlo da lagarta do funil do milho (Spodoptera frugiperda) na cultura do milho

Abstract

The fall armyworm (FAW) is an invasive and polyphagous pest, native to the continent American, where it has more than 350 hosts in addition to corn, its main host. It was detected in Africa in 2016 and in particular in Mozambique in 2017. chemical insecticides have been used more to control this pest, resulting in serious environmental problems. Many alternative methods have been recommended and studied, including botanical pesticides. The present study aimed to evaluate the effect of Botanical insecticides in the control of the fall armyworm (Spodoptera frugiperda). THE experiment was installed in the FAEF experimental field from January to June 2023, using the randomized complete block design (CBDB), with 4 treatments and 4 repetitions; 1 - Control, 2 - Azadirachta indica leaves, 3 - Biol (mixture of Aloe leaves vera, Calatropis procera, seeds of Tefrosia purpurea and Canavalia ensiformes, piripi (Cyperus giganteus) and tobacco (Nicotina tabacum) and 4 - Leaves of Calatropis procera. As for the level of infestation, the control treatment recorded the highest level of infestation (86.7%) compared to other treatments such as Calatropis procera (77.9%), Biol (72.9%) and Azadirachta indica (71.2%), however all treatments differed statistically from each other. Regarding the level of damage, the control treatment had an average scale of 5 (moderate damage, in scale of damage) meaning that the plants had holes in the leaves and funnel completely destroyed. The treatments Azadirachta indica, Biol and Calatropis procera recorded scale 3 (low damage) meaning that the plants had small circular lesions and some elongated in the funnel leaves. All treatments differed statistically from each other in terms of damage level. The control treatment obtained, statistically, a lower yield than corn grain in relation to treatments with botanical pesticides. However, treatments botanists did not differ statistically regarding grain yield. As for the estimate of yield losses if botanical insecticides had not been applied, the treatment Azadirachta indica had a yield loss of around (19.4%), Biol (22.32%) and Calatropis procera (17%). The application of treatments proved beneficial in controlling LFM, since the B/C Ratio is greater than 1. Higher net returns were found in use of Biol since it has a higher benefit/cost ratio(TRADUÇÂO NOSSA)