Field experiments were conducted in 1974 and 1975 to evaluate the effect of seven herbicides applied preemergence and two herbicides applied postemergence on weed growth around 7-yr-old pecan [Carya illinoensis(Wang.) K. Koch ‘Elliott’ and ‘Desirable’] and 3-yr-old peach [Prunus persica(L.) Batsch ‘June Gold’] and to observe herbicidal tolerance as noted from visually expressed phytotoxicity. After 12 weeks, the best control of bermudagrass [Cynodon dactylon(L.) Pers.], purple nutsedge(Cyperus rotundusL.), and wild blackberry (Rubus cuneifoliusPursh) was obtained with glyphosate [N-(phosphonomethyl)glycine], napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide] + glyphosate, and napropamide + terbacil (3-tert-butyl-5-chloro-6-methyluracil) + paraquat (1,1′dimethyl-4,4′-bipyridinium ion). The most effective overall control of yellow nutsedge (Cyperus esculentusL.), camphorweed [Heterotheca subaxillaris(Lam.) Britt. & Rusby], dogfennel [Eupatorium capillifolium(Lam.) Small], large crabgrass [Digitaria sanguinalis(L.) Scop.], and Florida pusley (Richardia scabraL.) resulted from napropamide + terbacil + paraquat. Herbicides used caused no visible toxicity to the immature pecan or peach trees.

No abstract

Methazole [2-(3,4-dichlorophenyl)-4-methy1-1,2,4-oxadiazolidine-3,5-dione] napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide], oryzalin [3,5-dinitro-N4,N4-dipropyl-sulfanilamide], oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-∆2-l,3,4-oxadiazolin-5-one], and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] each at 4.5 kg/ha were applied preemergence on June 17, 1976 in a nursery of 6-month-old seedlings of peach [Prunus persica (l.) Batsch cv. Nemaguard]. Though simazine and oryzalin provided better weed control, oxadiazon increased seedling height and trunk diameter from 25 to 89 days after application. All treatments impeded bark adhesion (slippage) 25 days after application but not after either 56 or 89 days. No phytotoxicity was observed from any treatment.

Anatomical and morphological similarities in flower and fruit development exist among cultivars of peach and nectarine [Prunus persica (L.) Batsch ‘June Gold’, ‘Harvester’, and ‘ArmKing’] and some other members of Rosaceae. The abscission of peach and nectarine fruit involves events at 3 recognizable zones between the fruit and the stem. Of these 3 zones, the most distal is the most complex and does not form a discrete separation layer. The basal zone is predominant in samples treated with the ethylene releasing compound, CGA-15281 [(2-chloroethyl) methyl-bis (phenlymethoxy) silane]. Mature fruit from untreated plants generally abscise at the most distal zone.