Management efficiency in cotton (Gossypium hirsutum L.) can be improved by implementing strategles that may be adjusted in response to expected or realized changes in plant growth and development. We propose that successive counts of main‐stem nodes bearing sympodia with a preflower fruiting structure in the first position are practical, dynamic measurements of plant development. A technique of monitoring number of main‐stem nodes above the sympodial branch bearing a white flower in the first position from the main axis (NAWF) was investigated. The physiological basis of NAWF was established by relating NAWF to other measurements of crop growth and yield. A critical value of NAWF was determined by retention, size, and number of seed associated with first‐position bolls. In separate tests, influences of cultivars, plant densities, irrigation, and two insect pests on NAWF were evaluated. The number of NAWF was closely related to variation in canopy photosynthesis indicating that growth activity of the crop can be monitored by NAWF. Based on individual boll measurements, potential economic value of flowers declined rapidly as NAWF approached 5.0. From regression equations of NAWF by days from planting, the number of days to NAWF of 5.0 (representing the last effective flower population) were calculated and used to distinguish effects of the management factors on plant development. Increased precision and confidence in end‐of‐season management decisions will likely be the first major benefit of this monitoring technique. As effects of additional management factors on NAWF are established, manipulation of the effective fruiting period and developmental pace of the crop should be possible by various combinations of factors, thereby providing a useful management tool.

The fungal entomopathogen, Beauveria bassiana (Balsamo) Vuillemin, was isolated from a naturally-infected tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), in Arkansas. This is the first report of a tarnished plant bug naturally infected with B. bassiana. In laboratory tests this isolate (ARSEF 3769) was highly infective to L. lineolaris nymphs and adults. The LC50 for nymphs and adults was 9 × 104 and 8.4 × lfj4 conidia per ml deionized water containing 0.01% Tween 80, respectively, when mortality was recorded 7 days after treatment. In a 1993 field test, cotton plants treated with ARSEF 3769 conidia at a rate of 5.8 × 107 conidia per ml deionized water containing 0.01% Tween 80 resulted in 88.8% and 100% mortality (n = 143) in exposed L. lineolaris adults at 5 and 7 days after treatment, respectively, compared with 7.4% and 11.4% mortality in the controls (n = 150). Persistence tests on field cotton showed that B. bassiana conidia could infect adult L. lineolaris for up to 4 days under ambient environmental conditions. A 1995 field test with the commercial B. bassiana product, Mycotrol WP, and the insecticide imidacloprid (Provado formulation) on L. lineolaris adults caged on canola resulted in 97.9% mortality at 5 days after treatment in L. lineolaris adults when Mycotrol (280 g per ha) and imidacloprid (50 g ai. per ha) were applied together, compared with 67.3% in the imidacloprid alone (50 g a.i. per ha), 52% in the Mycotrol alone (280 g per ha), and 7.6% and 13.6% mortality in the controls. The combination of Mycotrol and imidacloprid was significantly more effective than either material alone. These studies show that the fungus B. bassiana may be useful for control of L. lineolaris in cotton and other crops.

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