Impact of weed flora on aphid and thrips occurrence in pepper (Capsicum annuum L.) in the Strumica region

During 2024 and 2025, a research at two localities in the Strumica region (Kuklish and Borievo) was conducted in order to determine the qualitative composition of weed vegetation, their density and their role as reservoirs for aphids and thrips. Weed surveys were conducted using 1 m² plots randomly placed around pepper fields, while aphid and thrips occurrence was assessed through regular visual inspections during the growing season. A total of ten weed species belonging to nine botanical families were identified in Kuklish and eight species in Borievo, around pepper fields. The most dominant species in both localities in 2024 were
Galinsoga parviflora Cav., Chenopodium album Linn., and Amaranthus retroflexus L. In 2025, the dominant species in
Kuklish were G. parviflora, C. album, and Cyperus rotundus L., while in Borievo they were G. parviflora, C. album, and
Capsella bursa-pastoris L.. Weed density was higher in Kuklish than in Borievo, reaching 81.6 ± 11.19 and 62.0 ±
9.08 plants/m² in 2024, and 83.4 ± 15.69 and 70.8 ± 5.63 plants/m² in 2025, respectively. Aphids and thrips were
recorded on both weeds and pepper plants, with higher infestation levels observed in Kuklish than in Borievo
during both years. The number of infested pepper plants varied during the growing season. In both years of research and at both locations, thrips were more abundant than aphids. The results of the research showed that there was a strong positive correlation between the density and the abundance of aphids and thrips, especially thrips (r=0.823, p<0.001) and aphids (r=0.747, p<0.001), suggesting that weeds may act as alternative hosts for aphids and thrips. Therefore, effective weed management should be considered an important component of integrated pest management strategies in pepper production.