TETRACYCLINE THERAPY OF PEAR DECLINE AND X-DISEASE IN PEACH AND CHERRY

Oxytetracyclene HCL (Terramycin, Pfizer, Inc.) solution (50–100 ug/ml) transfused from reservoirs through plastic tubes and connectors into trees of pear affected with pear decline, and trees of peach and cherry affected with X-disease and buckskin, caused remission of symptoms the same season as the treatment and the one or more seasons following treatment.
Pear trees treated during the summer or early fall were without leaf curl symptoms that season.
The trees made excellent growth the following season and produced more and larger fruits than untreated trees.
Severely diseased trees required 2 or 3 consecutive annual treatments to make normal growth.
Peach trees after a single fall treatment were without X-disease symptoms for 2 consecutive seasons.
Mature cherry trees on Mazzard rootstock transfused with 6–8 litres of Terramycin solution 7–8 weeks prior to harvest produced fruits of normal size, color, and flavor which ripened 0–10 days later than fruit on healthy untreated trees.
The effect of the treatment carried over into the second and third season after treatment.
Spray applications of Terramycin agricultural formulation were also efficaceous in remitting symptoms of pear decline and cherry buckskin in affected trees the season the sprays were applied.
Concentrations of 500–2000 ppm were applied 1–6 times at weekly or biweekly intervals with and without summer oil.
Oil enhanced the effect of the sprays in cherry but not in pear.
A single annual post-harvest transfusion is recommended for pear and a single preharvest transfusion at first full leaf followed by a second early fall transfusion repeated when necessary is recommended for cherry.

IX International Symposium on Fruit Tree Virus Diseases

G. Nyland

https://doi.org/10.17660/ActaHortic.1975.44.1