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  • Author or Editor: J.D. Abbott x
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Cyromazine is a triazine molecule with insect growth regulator properties being developed for control of Colorado potato beetle (Leptinotarsa decemlineata Say) (CPB) in vegetables. Research presented focuses primarily on results with potato (Solanum tuberosum L.), however, crop safety has been observed in other crops within the Solanaceae. Several trials were conducted in PA and NY during 1991 to examine the rates and timing necessary to control CPB in potatoes. Data from replicated small plot trials and non-replicated large block trials are included. Rates examined ranged 70 to 560 g ai na-1 applied alone or in combination with a pyrethroid or Bt. Comparisons were made with insecticides presently registered for CPB control in potatoes and cyromazine compared quite favorably. Two applications per CPB generation were made, the first at the beginning of CPB egg hatch and a second 7-16 days later for each generation. This application schedule provided excellent (90%) control of CPB larvae. The reduction in larvae also resulted in a reduction in adult CPB and potato leaf area damaged through insect feeding. In the test conducted in PA, an increase in size and number of tubers was observed when plants were treated with cyromazine. -These increases resulted in a 23-28% increase in total yield compared to that obtained from the untreated check plots.

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Experiments were performed over 3 years to examine the effect that particle film (PF) treatment had on fruit quality of several apple (Malus ×domestica) cultivars in Washington and West Virginia. In the first study, a highly reflective, white, hydrophilic particle-based kaolin mineral (Surround WP) was applied to `Empire' apple in May and June, on a season-long basis, or not at all. Red fruit color was increased by both the PF treatments compared with no treatment in all years. In a second study, the PF material was applied, starting at petal fall, every week for 6 weeks and then every 2 weeks until harvest to `Empire', `Gala', and `Fuji' trees in West Virginia and to `Cameo', `Fuji', and `Gala' trees in Washington. In the latter study, cultivar response to season-long applications varied by year and location. `Empire' consistently had improved red color with season-long applications of PF materials. `Gala' had greater fruit weight and red color with PF application in 1 of 2 years in West Virginia but not in Washington. `Fuji' had greater fruit weight and soluble solids content and `Cameo' had greater soluble solids, higher starch indices, and greater red color in Washington with the PF application. In these studies, application of a PF never reduced the surface red color in apples. A taste panel did not identify quality differences in `Empire' apples treated with PF vs. the control. Cultivar responses to PF applications were variable due to location and yearly environmental characteristics. While particle film technology has value for insect control and reducing sunburn, it has limited value to enhance fruit color due to the inconsistent response.

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The sonic vibration characteristics of 5 major apple (Malus domestica Borkh.) cultivars were evaluated. The resonant frequency (f) and the mass (m) of individual intact apples were measured over 4 weekly harvests and again after 2½ and 5 months in storage. A nondestructive index of firmness, f2m, for each apple was calculated and compared with other measures of fruit texture. The f2m index was directly correlated with Magness-Taylor pressure test measurements of firmness and with sensory ratings of crispness, juiciness, and firmness, especially crispness. It was inversely related to mealiness. Correlations were affected by differences among cultivars; results were best and most consistent for ‘Golden Delicious’ and ‘Rome Beauty’.

Open Access