Managing Pratylenchus brachyurus in subsequent soybean crops following maize-brachiaria intercropping in greenhouse conditions

Abstract

Abstract This study aimed to evaluate how intercropping maize and brachiaria impacts the population dynamics of Pratylenchus brachyurus in subsequent soybean crops, both in greenhouse and field conditions. A secondary objective was to assess the effectiveness of two seed treatment nematicides in this crop system. The research involved ten sites where soybeans were grown after the maize-brachiaria intercropping, alongside fields with single maize or brachiaria cultivation for comparison. In addition, two experiments were conducted in pots in greenhouse. The treatments included maize-brachiaria intercropping with maize treated or non-treated with nematicides, followed by soybean treated or non-treated with the same nematicides, all in the presence of P. brachyurus. Nematode population analyses were conducted for both the intercropped maize and brachiaria, as well as the subsequent soybean plants. The findings indicated that P. brachyurus was the predominant nematode in the root samples, with higher representation observed in the presence of maize-brachiaria intercropping. In both experiments, fluopyram exhibited superior efficacy against the lesion nematode compared to B. firmus when applied to soybean after intercropping of maize and brachiaria. Importantly, intercropping maize and brachiaria without nematicides led to the persistence of P. brachyurus populations, potentially causing issues in subsequent soybean crops. The data suggests that incorporating brachiaria in intercropping with maize contributes to the proliferation of P. brachyurus. However, the study demonstrated that this negative impact could be mitigated by implementing chemical and/or biological nematicides throughout the crop season. Hence, while intercropping systems involving maize-brachiaria may worsen problems caused by P. brachyurus in infested fields, appropriate nematicide application can effectively manage nematode populations and minimize potential harm to crops.