Dr. Lukasz Stelinski has found that the presence of psyllids in a citrus grove will decrease fruit yields, even in trees that are not infected with HLB.
Renowned entomologist Dr. Lukasz Stelinski recently spoke to Florida Citrus Mutual about the impact of psyllids on the health of citrus trees. Psyllids are the vector by which citrus greening, or HLB, is transmitted to citrus trees. “Reducing psyllids improves tree health, even in trees that have HLB,” Stelinski says.
According to Stelinski, damage to the trees is proportional to the density of the pests, susceptibility of the crop, and the time of the interaction between the pest and the crop. Therefore, reducing the density of psyllids will benefit the trees. This can be accomplished through a dual approach of eliminating the pests and increasing the resistance of the trees to the damage caused by psyllids.
Insecticides can be effective against psyllids. Trees that are treated for these little sap-suckers have been shown to have increased yields at harvest time. This is proven to be true in trees that are already infected with HLB. In fact, the presence of a psyllid infestation will decrease yields even in trees that are not infected with HLB. Of course, the greatest damage to trees is caused by the presence of psyllids combined with an HLB infection.
Basically, what happens is that the activity of psyllids on the tree inhibits the expression of certain plant genes that are integral in the plant’s defense. This compromises the plant’s defense reaction to the HLB pathogen.
It is already known that psyllids can be controlled in a grove with heavy spraying – 10 or 12 times a year. This isn’t really sustainable, environmentally or economically sound, so Stelinski came up with an alternate plan with 3 or 4 carefully timed sprays. After harvest, a dormant spray should be applied before the spring flush. Then spray for adult psyllids exactly at bud break, and again on the flush. One more spray should be applied when the psyllids reach their threshold level. This spray schedule seems to be effective but must be performed irrespective of the harvest schedule.
Another natural control option to help manage psyllids is planting windbreaks such as Torelliana Eucalyptus and bamboo. Call us in supplying your windbreak needs.