Fruit Times

Apple scab lesions appeared April 17 on trees that were not adequately protected March 20-25. This could have led to severe secondary infection April 18-23. Proper and thorough coverage at this time of the year is critical for preventing infection of young fruits. This article contains updates on pome and stone fruit diseases and new fungicide properties.

Earlier this year, a podcast series “Social Media and Food Retailers: Consumer Perspectives” was released on YouTube to describe the results of a consumer study designed to better understand how consumers use social media to engage with food retailers. Social media tools (Facebook, Twitter, blogs, etc.) allow for two-way communication between the consumer and the food retailer, and these research results provide important insights for food retailers interested in enhancing their marketing efforts.

Looking at the comparisons of accumulated degree-days (base 43) for the last 6 years, as of April 20 we are still about 100-150 DD ahead from any other year or about 200-300 DD ahead of the average DD accumulation for this time of the year. And while this difference is becoming smaller as the spring progresses (especially when compared to the weather pattern during the spring of 2010 season), this unusual weather seems to have caused a lot of confusion in the insect world that surrounds our fruit trees.

Given the growth stage of berry crops and the current weather, frost protection is on everyone’s mind. In this update, you will find a re-run of a portion of a frost-related article, and some frost-related “Berry Good Questions” from past years paraphrased and condensed, plus a couple of new ones thrown in. Most of this information is also contained in Appendix A in the Mid-Atlantic Berry Guide, along with a lot of other frost-protection information.

PA MarketMaker, wants to help Pennsylvania agricultural businesses make a splash online by showcasing delicious foods made with Pennsylvania strawberries on Pinterest.com. Submissions will be pinned to the “PA MarketMaker Pinterest Contest” Pinboard, where consumers from around the globe may see your recipe and learn about your business.

We have known for more than 80 years that post-bloom temperatures can influence harvest date, but not until recently have we realized that post-bloom temperatures can also affect fruit size at harvest.

As you train your high density orchards this spring, keep in mind some underlying components ("blueprint") for a successful intensive apple system.

The Orchard Spray Record Spreadsheet has been updated for 2012 with 26 new pesticides and herbicides. This is an easy-to-use tool to help growers keep track of spray records with individual sheets for Apples, Peaches, Cherries and Pears. The spreadsheet is set up with drop-down lists for easier and faster completion. It will keep track of the various products used and maintain a cost summary.

As explained at the orchard twilight meeting last week, we expected and found the first scab lesions today on non-sprayed check trees of Delicious, Golden Delicious, Cortland and Stayman.

Several cold temperature events before and during bloom occurred in 2012. This resulted in apple flower mortality, and there is also a possibility of some non-lethal injury to flowers and/or spur leaves. This leads to some uncertainty about the number and strength of initial fruit set.

If you are in an area prone to cedar-apple or quince rusts, many of the apple scab wetting periods were also favorable for rust infection.

If there is wetting during the anticipated warm-up on April 15th to 17th, there is the potential for severe fire blight infections.

Apple scab lesions should be expected this week on trees that were not adequately protected March 20th to 25th. Any infections could lead to a severe secondary infection on April 17th, given the current weather forecast.

Based on conditions at the Penn State Fruit Research and Extension Center and the Sky Bit Ag E-Weather Apple IPM Disease Report, the potential for fire blight infections may occur during the upcoming weekend.

Apple scab infection periods and predicted infections through April 17th for the Penn State Fruit Research and Extension Center are attached.

A possible link between neonicotinoids and honey bee die-offs has led to controversy across the United States and Europe. Beekeepers and environmentalists have expressed growing concern about the impact of neonicotinoids, concern based on the fact that neonicotinoids are absorbed into plant tissue and can be present in pollen and nectar, making them toxic to pollinators.

Flower mortality following Monday's low of 28 degrees F at the Penn State Fruit Research and Extension Center in Biglerville was assessed with an Equilifruit disk designed for determining how much to thin apples following fruit set. Although flower mortality on the most advanced variety, was 49%, limbs still had 4 to 10 times as many live flowers as needed for a full crop.

Actual and predicted apple scab infections for Penn State FREC, based on the Campbell Scientific Weather Data System and the New Mills Apple Scab Disease Model, are now posted.

Apple fruit bud development at the Penn State Fruit Research and Extension Center in Biglerville is pre-pink to pink, with a few blossoms open on Pink Lady. Fire blight risk to date, based on the MaryBlyt Prediction Program and Campbell Scientific Weather Data Systems, are presented in the attached graph.

Tree fruit crops are in various stages of bloom and freezing temperatures are a concern. The temperature at which fruit buds are injured depends primarily on their stage of development.