Anjou Pear Quality: Disorders and Diseases
This is the third part of a summary report of research activities for 1991, 1992, and interim report for the 1993 crop. Please consult "Anjou Pear Quality: Fruit Quality" for survey design.
Postharvest cullage of Anjou pears had been reported to be of significance by some packinghouse managers. To put dollar figures on the extent of postharvest losses, Dave Burkhart interviewed warehouse managers following each marketing season. Managers reported postharvest losses for the 1990 crop in excess of $1.7 million among those shippers who handled over 100,000 boxes. These managers reported losses of $1.4 million for the 1991 crop. Warehouse managers handling over 40,000 boxes were surveyed and reported losses of $2.2 million for the 1992 crop year.
It is important to understand the reasons for these losses and what can be done to avoid them in the future. Managers reported different reasons for losses each year. It is obvious that these losses are severe and the industry must embark on a program to reduce their magnitude. Responses from warehouse managers indicate that fungal diseases such as blue and gray mold caused severe postharvest losses in 1992 in most of the packinghouses surveyed. It is more difficult to obtain an assessment of the dollars lost for each malady.
Defects and diseases can be considered here only in light of the 1991 and 1992 crops since the 1993 crop is not scheduled for final analysis until June 1994. Using data from fruit stored in the 1991 and 1992 crop years, observations can be made about fruit disorders and diseases. Table 1 tabulates the defects and disorders following either midterm or long-term CA storage from both years. The numbers are industry averages rather than problems encountered in individual packinghouses. There was no moldy core present in any of the samples. There was very little skin speckling, pithy brown core, cuts, or scald. There were, however, some punctures and a good deal of russeting and limb rub. None of these were related to time in storage.
Scuffing did not increase over time in storage, but was of concern. There was more scuffing noted in the 1991 crop than in 1992. Shrivel was quite serious in some lots. It did not increase over time. Decay was very serious in fruit samples in 1992 but not in the 1991 crop. Decay increased with time in storage from 2% in April to 6% by June.
Table 1. Decay and diseases for the 1991 and 1992 Anjou crops following midterm or long-term storage. Figures are industry averages.
|Mid CA||Late CA||Overall|
|*Numbers are % of fruit examined.|
Defects in Fruit from Individual Packinglines
Table 2 collates the range of defects on fruit that emerged after warm room ripening from the 1992 crop from packinglines following storage until late May. Of particular interest is the number of packinglines with scuffed fruit.
Table 2. Number of packinglines having fruit with various defects in 1992.
|* Higher scores=more serious problems|
Decay in Fruit from Individual Packinglines
A significant amount of decay was found after storage from fruit on certain packinglines (Table 3). The major types of fungal decay were blue mold (82%), gray mold (15%), and mucor rot (2%).
Table 3. Number of packinglines with decayed fruit in 1992.
|% Decayed fruit||Midterm||Long-term|
ConclusionManagers reported problems similar to those seen in fruit samples. Decay was the most serious problem, with shrivel also important. Fruit scuffing also deserves attention.
Certain packinghouses have lost large sums of fruit due to postharvest decay or disorders while others have lost little. This next season we will identify those packers, isolate reasons for cullage, and identify possible solutions.
Dr. Eugene Kupferman, Postharvest Specialist
WSU Tree Fruit Research and Extension Center
1100 N. Western Ave., Wenatchee, WA 98801
Tree Fruit Postharvest Journal 5(1):14-16