Effects of Skip-Row Planting Pattern and Planting Date on Dryland Cotton Insect Pest Abundance and Selected Plant Parameters

摘要

Three planting-date windows [early aa 3 weeks before (i.e., 26aa29 April) the recommended optimum planting window; timely aa the commonly recommended optimum planting window of 16aa19 May; and late aa 3 weeks after (i.e., 6aa9 June) the recommended optimum planting window] and three planting patterns (Solid aa solidrow stand; Skip 2AA1 aa two rows planted, one row skipped; and Skip 2AA2 aa two rows planted, two rows skipped) were evaluated to determine their influence on abundance and population dynamics of arthropods during 3 years in cotton, Gossypium hirsutum L., on the Texas Rolling Plains. Arthropod species sampled included thrips, Frankliniella occidentalis (Pergande); cotton fleahopper, Pseudatomoscelis seriatus (Reuter); cotton aphid, Aphis gossypii Glover; and bollworm, Helicoverpa zea (Boddie). Planting date significantly influenced aphid abundance. Fewer aphids were found in early-planted cotton (1.0 per leaf) compared with timely (2.3 per leaf) or late (1.8 per leaf) planted cotton. Similarly, bollworms were more abundant in early- and late-planted cotton (157 and 204% greater, respectively) than in optimally planted cotton. Planting pattern did not significantly influence abundance of thrips or cotton fleahopper. Conversely, consistently more cotton aphids (2.2 per leaf) were found in Skip 2AA2 planted cotton, followed by Skip 2AA1 (1.8 aphids per leaf) and Solid (1.2 aphids per leaf). Abundance of bollworms did not significantly vary with planting pattern. With fewer planted rows, Skip 2AA2 yield, at 348 kg per hectare, was significantly less than that of Skip 2AA1 (414 kg per hectare) or Solid (409 kg per hectare), yet marked improvement in most lint-quality parameters was noted for both skip-row plantings. This study provides evidence that a Skip 2AA1 planting pattern in mid-May seems to be the best production scenario for dryland cotton in the semi-arid region of Texas.