Trials conducted with UC Extension since 2003 show that ReTain® PGR consistently increases yields in orchards with PFA.
ReTain reduces ethylene production in pistillate (female) flowers, which is the main cause of PFA. This results in increased nut retention and higher yields.
By applying ReTain twice a grower can protect a larger number of flowers — those that bloom early and those that bloom later — and achieve both increased nut set and profit potential. The best time for growers to apply ReTain to walnuts is in late March or early April, waiting 2-4 days between applications. If it’s warm during this time, growers should wait no more than two days between applications. If the weather is cooler, come back four days after the initial application and apply again.
The initial application should be made at 30 percent of pistillate (female flower) bloom, with the second at 40 percent to 60 percent bloom.
While historically Serrs respond very well to multiple ReTain applications, recent research has shown promising results in other varieties as well.
For example, two full-rate applications of ReTain delivered the most profitable yield in Tulare orchards, as opposed to just one application or no applications of ReTain. PFA-affected Chandler and Hartley cultivars responded more moderately. However, at today’s prices it is still profitable to apply ReTain where PFA is a problem in these varieties.
To learn more about ReTain and the rest of Valent’s portfolio of tree nut products, visit www.valent.com.