ABSTRACT
The fall armyworm [FAW; Spodoptera frugiperda (J.E Smith, 1797)] is an invasive and polyphagous insect that infests cereal crops, causing economic losses, and may be led to pose a threat to future the global maize crop in the future. Field trials were conducted to study the negative impacts of S. frugiperda on vegetative growth measurements, yield, and the components of the maize cultivar (Single-Hybrid 168 Yellow) in Luxor Governorate, Egypt. S. frugiperda larvae infestation to maize plants was observed in the 3rd week of June and so continued till the harvest in both 2021 and 2022 seasons. S. frugiperda had three peaks of the seasonal activity/season in the untreated (pesticide-free, control) and in the treated main plots by pesticides. Maize vegetative growth attributes (averages of plant height, stem diameter, and the number of green leaves per plant) displayed higher rates of the treated maize plants by insecticides against S. frugiperda. Maize grain, straw, and biological yield (kg/ha) were decreased in the untreated maize plants (insecticides free) than in the treated by insecticides. Concerning maize yield components, the treated plants were to outperform in the average length of a plant stem (cm), stem diameter (cm), and weight of cob (g), as well as, number of rows/cob, number of grains/ cob, number of grains/cob, maize cob grain weight (g) and weight of 1000-grains (g)], in comparison with the untreated plants. Also, the FAW infestation to untreated maize plants was decreased well in all calculated maize growth attributes, i.e., grain yield, and components. Regarding the relationship between variations in a given variable and the changes in S. frugiperda larvae numbers and plant damage percentage, the simple correlation and regression coefficient revealed a highly significant negative relationship in all the parameters tested. The obtained information may help farmers and decision-makers in the management of FAW populations based on an effective plan related to control measures that should be implemented.
A lagarta-do-cartucho [FAW; Spodoptera frugiperda (J.E Smith, 1797)] é um inseto invasor e polífago que infesta culturas de cereais, responsável por perdas econômicas, representando uma ameaça para a cultura mundial de milho no futuro. Ensaios de campo foram conduzidos para estudar os impactos negativos de S. frugiperda nas medidas de crescimento vegetativo, rendimento e os componentes da cultivar de milho (Single-Hybrid 168 Yellow) na província de Luxor, Egito. A infestação de larvas de S. frugiperda nas plantas de milho foi observada na terceira semana de junho e prosseguiu até a colheita nas temporadas de 2021 e 2022. A espécie S. frugiperda teve 3 picos da atividade sazonal nas parcelas não tratadas (sem agrotóxicos e controle) e nas tratadas com agrotóxicos. Os atributos de crescimento vegetativo do milho (médias de altura da planta, diâmetro do caule e número de folhas verdes por planta) apresentaram maiores taxas das plantas de milho tratadas com inseticidas contra S. frugiperda. O grão de milho, a palha e o rendimento biológico (kg/ha) diminuíram nas plantas de milho não tratadas (sem inseticidas) do que nas plantas tratadas com inseticidas. Com relação aos componentes de rendimento do milho, as plantas tratadas tiveram desempenho superior no comprimento médio do caule da planta (cm), diâmetro do caule (cm) e peso da espiga (g), bem como, número de fileiras/espiga, número de grãos/espiga, número de grãos/espiga, peso de grãos de espiga de milho (g) e peso de 1000 grãos (g), em comparação com as plantas não tratadas. Além disso, a infestação de LFM em plantas de milho não tratadas diminuiu consideravelmente em todos os atributos de crescimento do milho calculados, ou seja, rendimento de grãos e componentes. Quanto à relação entre as variações de uma determinada variável e as mudanças no número de larvas de S. frugiperda e na porcentagem de danos às plantas, a correlação simples e o coeficiente de regressão revelaram uma relação negativa e altamente significativa em todos os parâmetros testados. A informação obtida pode ajudar os agricultores e gestores das populações da LFM com base num plano eficaz relacionado às medidas de controle que devem ser implementadas.
Subject(s)
Pesticides , Spodoptera , Agricultural Pests , Zea mays/parasitologyABSTRACT
The fall armyworm [FAW; Spodoptera frugiperda (J.E Smith, 1797)] is an invasive and polyphagous insect that infests cereal crops, causing economic losses, and may be led to pose a threat to future the global maize crop in the future. Field trials were conducted to study the negative impacts of S. frugiperda on vegetative growth measurements, yield, and the components of the maize cultivar (Single-Hybrid 168 Yellow) in Luxor Governorate, Egypt. S. frugiperda larvae infestation to maize plants was observed in the 3rd week of June and so continued till the harvest in both 2021 and 2022 seasons. S. frugiperda had three peaks of the seasonal activity/season in the untreated (pesticide-free, control) and in the treated main plots by pesticides. Maize vegetative growth attributes (averages of plant height, stem diameter, and the number of green leaves per plant) displayed higher rates of the treated maize plants by insecticides against S. frugiperda. Maize grain, straw, and biological yield (kg/ha) were decreased in the untreated maize plants (insecticides free) than in the treated by insecticides. Concerning maize yield components, the treated plants were to outperform in the average length of a plant stem (cm), stem diameter (cm), and weight of cob (g), as well as, number of rows/cob, number of grains/ cob, number of grains/cob, maize cob grain weight (g) and weight of 1000-grains (g)], in comparison with the untreated plants. Also, the FAW infestation to untreated maize plants was decreased well in all calculated maize growth attributes, i.e., grain yield, and components. Regarding the relationship between variations in a given variable and the changes in S. frugiperda larvae numbers and plant damage percentage, the simple correlation and regression coefficient revealed a highly significant negative relationship in all the parameters tested. The obtained information may help farmers and decision-makers in the management of FAW populations based on an effective plan related to control measures that should be implemented.