Issue link: https://read.dmtmag.com/i/473131
32 MARCH 15, 2015 GOOD FRUIT GROWER www.goodfruit.com M echanical pollination shows promise for manag- ing the crop load in cherry and apple orchards, preliminary research at Washington State University indicates. With the threat of declining honeybee numbers in the United States, crop pollination has become an important issue facing agriculture. A national call for bee research resulted in projects focused on finding alternate pollinators, improving habitat for pollinators, and solving colony collapse disorder. The call also triggered the start of a small project that ultimately could make bee pollinators and pollinizers unnecessary in some tree fruit and vegetables crops. WSU's Dr. Matthew Whiting, cherry horticulturist, and Probir Das, WSU graduate student, spent last year working on research to prove that using an orchard sprayer to pollinate tree fruit is a viable concept. The preliminary study showed that pollen can be suspended in solution, maintaining viability for at least an hour, and can be applied through a commercial electrostatic sprayer, with minimal modification. Moreover, the pollen reached the flower stigmas and shows potential to supplement or replace the current system that relies on pollinizers and pollinators. The proof-of-concept study involved field and laboratory trials. Field work, conducted in several orchards with multiple apple and cherry varieties, involved using an electrostatic sprayer to make two applications of pollen at three different rates. Trees were netted to keep bees out, and pollen was sprayed when 50 percent and 90 percent of the flowers were open. Scientists eval- uated pollen viability of three sweet cherry pollen genotypes and developed a formulation that would suspend pollen in solution, move through the sprayer system without clogging, and maintain pollen viability long enough to stick to the flower stigmas and fertilize the ovules. Fruit set was 15 percent higher in one cherry orchard that was mechanically pollinated than when natural pollination was used, Das reported during winter tree fruit talks in Washington. In the apple trial, which evaluated two different pollen solutions, fruit set increased 56 and 75 percent compared to natural pollination. "We are really at the initial stage in research and are now just really getting started," Whiting told Good Fruit Grower. "We proved that it was possible to put live tissue (pollen) through a pressurized sprayer, with its filters and nozzles, have it survive all that and still be alive, and then land on a tiny stigma and result in a viable fruitlet." Whiting and his research team are working this year on a full-scale project funded by the Washington Tree Fruit Research Commission. He is working with On Target Spray Systems, using one of their ATV-pulled electrostatic sprayers, and Firman Pollen, Pollination Mechanical pollination could end use of chemicals or hand labor for thinning. by Melissa Hansen Precision POLLINATION COURTESY MATT WHITING / WASHINGTON STATE UNIVERSITY Washington State University researchers have shown it's possible to use a sprayer to place live pollen on blossoms and result in a fruitlet.