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- Author or Editor: Nancy L. Schulte x
An infrared CO2 analyzer system was used as a nondestructive and rapid means of monitoring the CO2 evolution of blueberries (Vaccinium corymbosum L.), sweet cherries (Prunus avium L.), and tart cherries (P. cerasus L.). An increase in the CO2 evolution of blueberries and cherries caused by impact-induced bruising was correlated with percent product decay. This technique may be useful in evaluating bruise damage caused by harvesting and handling systems.
`Redhaven' peaches [Prunus persica (L.) Batsch] were dropped onto several impact surfaces to determine impact conditions that initiate bruising. After impact, the peaches were tested for flesh firmness and sorted into firm, soft, and very soft groups for bruise analysis. The drop height that did not bruise decreased as fruit softened. The peach shoulder area bruised most easily. A drop of only 8 mm onto a hard surface initiated bruising on a soft peach, whereas a Poron 15250 cushion could protect the peach for a ≤85-mm drop. Impact damage threshold estimates were developed for the three flesh firmness conditions. The threshold estimates and impact history information collected by an instrumented sphere can be used to develop handling equipment design and operation guidelines that essentially avoid impact bruises on peaches.
A screen to test for resistance to blueberry shoestring virus (BBSSV) was developed using rub inoculation and the ELISA technique. A high rate of infection can be obtained with a virus concentration of 0.25 mg/ml when it is applied to randomly selected leaves of container grown blueberries during any portion of the growing season. However, plants must be ELISA tested in the early spring or 5 times during the rest of the growing season to achieve >50% accuracy.
Sixteen cultivars of blueberry (Vaccinium corymbosum L.) were field screened for resistance to the blueberry aphid Illinoia pepperi (McGillivary), the vector of blueberry shoestring virus. Significant differences were observed with ‘Bluejay’, ‘Northland’, ‘Bluetta’ and ‘Bluehaven’ supporting the lowest numbers, while ‘Spartan’, ‘Darrow’, ‘Lateblue’, ‘Coville’ and ‘Jersey’ carried the highest numbers. There was no significant correlation between aphid number and new shoot number, percentage of shoots with new growth, length of new growth, leaf length or leaf width. Half of the aphids were found in the lower 1/3 of the bushes.