Efficiency of metamitron as postbloom thinner in ‘Red Jonaprince’ and ‘Golden Delicious’

Radivojević, D.; Milivojević, J.; Oparnica, Č.; Pavlović, M.

doi:10.17660/actahortic.2020.1289.8

Cited by 1 publication

(1 citation statement)

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“…In another study on Gale Gala, observed that 350 mg L −1 MET reduced fruit set when applied at 18 mm fruitlet diameter. Radivojevic et al (2020) observed that application of 250 mg L −1 MET to Golden Delicious at 16-18 mm fruit diameter was very effective in reducing fruit set. In a Chilean study, Reginato et al (2017) found that 450 g MET ha −1 , applied between 4 mm (petal fall) and 28 mm fruit diameter, effectively thinned Brookfield Gala trees, even when the trees were predicted to have a strong carbohydrate balance, especially during the later application timings.…”

Section: Effect Of Fruit Developmentfruitlet Diametermentioning

confidence: 98%

Multi-year investigation on the rate, timing, and use of surfactant for thinning apples with post-bloom applications of metamitron

2022

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Several experiments were conducted in Simcoe, Ontario to evaluate the efficacy of metamitron (MET) as a post-bloom thinner for Ambrosia, Gala, and Honeycrisp apple trees. Trees were treated with rates of MET ranging from 165-480 mg.L-1, as well as different timings ranging from 5-22 mm fruit diameter. The effect of including a non-ionic surfactant on thinning efficacy with MET was also evaluated. Treatments were compared with untreated trees and industry standard sprays of carbaryl, NAA, 6-BA, or combinations thereof. Response to MET varied by cultivar and season. In six of the seven experiments, MET reduced fruit set, but in only four did MET reduce the number of fruit per tree or crop load compared with the untreated control trees. Petal fall (5-7 mm) applications of MET were less effective than later timings. Thinning response increased with higher rates of MET in four of the seven studies. For Honeycrisp and Ambrosia, 175 mg.L-1 MET was effective in reducing fruit set and crop load, while rates at or above 263.mg L-1 MET were required to thin Gala. MET improved fruit size distribution into larger categories and caused minimal leaf phytotoxicity with or without a non-ionic surfactant. Environmental factors such as nighttime temperature and solar radiation largely could not account for the seasonal or application timings in thinning response to MET. Greater understanding of the carbon balance and interplay of solar radiation, nighttime temperature, cultivar and fruitlet size on thinning response is required to improve the predictive thinning response of apple to MET.

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Section: Effect Of Fruit Developmentfruitlet Diametermentioning

confidence: 98%