A common practice in highbush blueberry (Vaccinium corymbosum L.) culture is to use combinations of insecticides and fungicides to reduce the number and cost of pesticide applications. In response to apparent phytotoxicity observed in commercial fields that were treated with combinations of diazinon and captan formulations, phytotoxicity of two formulations of diazinon (Diazinon AG600 and Diazinon 50W) and captan (Captan 80WP and Captec 4L) was investigated on highbush blueberries during 1997 and 1998. Phytotoxicity injury similar to injury observed in commercial fields was reproduced in treatments with diazinon and captan mixtures in all experiments. The Diazinon AG600 and Captec 4L mixture was the most severe and caused significantly more phytotoxic-ity to fruit and leaves than individual treatments of Diazinon AG600, Captec 4L or untreated control. Separation of diazinon and captan applications by 8 h significantly reduced phytotoxicity compared to mixture treatments. Injured fruit and leaves recovered over time and most treatments showed only a mild injury at the time of harvest. Phytotoxicity on fruit and leaves caused by Diazinon AG600 and Captec 4L mixture was significantly affected by application date with the earliest application causing the greatest injury. These data indicate that diazinon and captan mixtures cause phytotoxicity on highbush blueberries and therefore the two should not be applied in combination.
David Campbell, Ali Sarkhosh, Jeffrey K. Brecht, Jennifer L. Gillett-Kaufman, Oscar Liburd, Juan Carlos Melgar, and Danielle Treadwell
for all fruit injury measurements are presented by year for simplicity ( Table 3 , Fig. 4 ). Quadrant had no effect on fruit injury rating. Bagging fruit reduced mechanical injury by 3.9% compared with not bagging ( P = 0.04). Mandibulate
Thomas M. Kon, James R. Schupp, Keith S. Yoder, Leon D. Combs, and Melanie A. Schupp
evaluated over-thinned or increased fruit injury to commercially unacceptable levels. Also, initial fruit set was reduced by compounds that were proven to inhibit pollen tube growth in vivo, which is a desirable outcome. Limited fruit injury was attributed
Mark A. Williams, John G. Strang, Ricardo T. Bessin, Derek Law, Delia Scott, Neil Wilson, Sarah Witt, and Douglas D. Archbold
materials for fertility, and disease, insect, and weed control, to assess tree growth, tree and fruit injury from insect pests and diseases, and yield. In Phase 2, beginning in 2014, strategies to address major limitations and/or problems identified in Phase
Elhadi M. Yahia and Martin Tiznado Hernandez
`Keitt' mangoes (Mangifera indica L.) were stored for 0 to 5 days at 20C in a continuous flow of an insecticidal low-O2 atmosphere (0.2% to to 0.3%, balance N2). Fruit were evaluated every day after exposure to a low-O2 atmosphere and again after being held in air at 20C for 5 days. There was no fruit injury, organoleptic fruit quality was not lowered due to the low-O2 atmosphere, and fruit ripened normally. These results indicate that applying low-O2 atmospheres postharvest can be used to control insects in mangoes.
Sergio Castro-Garcia, Uriel A. Rosa, Christopher J. Gliever, David Smith, Jacqueline K. Burns, William H. Krueger, Louise Ferguson, and Kitren Glozer
Table olives (Olea europaea) traditionally are hand harvested when green in color and before physiological maturity is attained. Hand harvesting accounts for the grower's main production costs. Several mechanical harvesting methods have been previously tested. However, tree configuration and fruit injury are major constraints to the adoption of mechanical harvesting. In prior work with a canopy shaker, promising results were attained after critical machine components were reconfigured. In this study, stereo video analysis based on two high-speed cameras operating during the harvesting process were used to identify the sources of fruit damage due to canopy-harvester interaction. Damage was subjectively evaluated after harvest. Fruit mechanically harvested had 35% more bruising and three times as many fruit with broken skin as that of hand-harvested fruit. The main source of fruit damaged in the canopy was the strike-impact of fruit by harvester rods. Implementation of softer padding materials were effective in mitigating fruit injury caused by the impact of rods and hard surfaces. Canopy acceleration was correlated with fruit damage, thus restricting improvements needed for fruit removal efficiency through increased tine frequency.
M. Tiznado, E.M. Yahia, and L. Vazquez-Moreno
Mango fruits (cv Keitt) were exposed to a continuous flow of low O2 atmosphere of 0.1 to 0.2% (balance is N2) for 0 to 5 days at 20°C. Fruits were evaluated every day after exposure to low O2 atmosphere, and again after 5 days in air at 20°C. A sensory evaluation test was conducted after 15 days from the initiation of the experiment. The low O2 atmosphere reduced the activity of the enzymes malic dehydrogenase and isocitric dehydrogenase but did not affect the activity of α- Ketoglutarate dehydrogenase. However, there was no indication of any fruit injury nor any detrimental organoleptic changes due to the low O2 atmosphere. These results suggest the possibility of the application of very low O2 atmosphere for postharvest insect control in mango.
Elhadi M. Yahia, Marisela Rivera, and Omar Hernandez
Papaya (Carica papaya L., cv. Sunrise) fruits were exposed to a continuous flow of an atmosphere containing <0.4% 02 (the balance being N2) for 0 to 5 days at 20C. Decay was a major problem, and some fruit had developed off-flavors after 3 days in low O2 plus 3 days in air at 20C. The intolerance of the fruit to low O2 correlates with an increase in the activity of pyruvate decarboxylase and lactate dehydrogenase but not with the activity of alcohol dehydrogenase. Insecticidal O2 (< 0.4%) atmospheres can be used as a quarantine insect control treatment in papaya for periods <3 days at 20C without the risk of significant fruit injury.
J.T. Raese and S.R. Drake
Calcium sprays (CaCl2, Mora-Leaf-Ca + Link Ca, or Stopit) increased fruit Ca concentrations and reduced the incidence of cork spot of `Anjou' pears (Pyrus communis L.) during four seasons. All Ca sprays increased yield relative to the control. All sprays resulted in some injury to leaves and fruit, but fruit was acceptable for marketing. At the low rate, Stopit sprays were the least injurious. Early season sprays, in June to July, produced less leaf and fruit injury than late-season sprays, in July to August, or early + late-season sprays. Early or late-season Ca sprays resulted in slightly larger fruit than early + late sprays. Either late or early + late-season sprays led to higher Ca concentrations in fruit cortex than early sprays.
J.R. Schupp, T.L. Robinson, W.P. Cowgill Jr., and J.M. Compton
Three experiments were conducted on `Empire' apple (Malus ×domestica Borkh.) to evaluate the effects of hard water, calcium chloride (CaCl2), water conditioners, surfactants, and captan fungicide on the growth reduction and fruit cracking caused by prohexadione-calcium (PC). Two applications of 63 mg·L-1 PC provided season-long growth control in two studies. Adding a water conditioner to PC reduced shoot growth more than an application of PC in hard or soft water in one New York study. Ammonium sulfate (AMS) and Choice were equally effective water conditioners. PC provided no growth control of water sprouts and had no effect on fruit set or yield. PC applied at 250 mg·L-1 reduced fruit size. `Empire' fruit cracking and corking was severe, despite the use of only 63 mg·L-1 PC in two of the three experiments. This damage was exacerbated by the addition of a water conditioner, however AMS applied with a surfactant but without PC had little or no effect on either the severity or extent of fruit injury. In a third experiment, the addition of surfactants, CaCl2, or captan to 250 mg·L-1 PC plus a water conditioner had no effect on the severity of fruit damage. Fruit cracking caused by PC increased preharvest drop in two of three experiments, and increased postharvest rot in the Geneva, N.Y., experiment where fruit were stored prior to grading. Application of PC plus a water conditioner reduced estimated gross return per hectare for `Empire. We conclude that the fruit injury is caused by the formulated PC product itself under certain environmental conditions, and that this product should not be used on `Empire. Chemical name used: calcium 3-oxido-4-proprionyl-5-oxo-3-cyclohexine-carboxylate [prohexadione-calcium (PC)].