The state of Texas suffers from a lack of chilling one out of every five years. Reduced yield in temperature fruit crops such as peach (Prunus persica) is one detrimental effect associated withinadequate chilling. Field trials with hydrogen cyanamide (Dormex) have demonstrated that a one to two percent solution applied six weeks prior to bloom will substitute for inadequate chilling of up to 150 hours. Field trials with this chemical have provided further insight into some other possible benefits associated with its use such as: increased marketable yields of fruit crops, enhanced fruit size, and an earlier more concentrated harvest. Advantages noted by the use of this product include a possible earlier crop and reduced labor costs.
Jason C. Powell and Calvin G. Lyons
Ross E. Byers, K.S. Yoder and C.G. Lyons
Own-rooted `Redhaven' and `Cresthaven' peach [Prunus persica (L.) Batsch.] trees and `Redhaven' and `Cresthaven' on Lovell seedling rootstock were planted in fumigated and nonfumigated areas of a site where peach trees previously displayed peach stem-pitting (PSP) symptoms. The combined incidence of stem pitting of the `Redhaven' and `Cresthaven' peach trees was 16% on nonfumigated soil in the 10 years of the study. The combined stem-pitting incidence of own-rooted trees (9.1%) was significantly lower than on Lovell roots (22.1%). Incidence of PSP in the adjacent fumigated areas was relatively low (1% Lovell and 4% own-rooted) and, therefore, precluded a comparison of own-rooted and Lovell-rooted trees. Within affected sections of rows, 67% of the `Cresthaven'/Lovell and 64% of the `Redhaven'/Lovell trees had PSP symptoms, but only 25% of own-rooted `Cresthaven' and 18.8% of own-rooted `Redhaven' trees were symptomatic. Although these data suggest that rooted cuttings of these cultivars may be less susceptible to stem pitting, the use of rooted cuttings does not eliminate fumigation as a means of providing acceptable stem-pitting management in a heavily infested site.