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Abstract
Oryzalin, simazine, and metolachlor alone and in combination were evaluated for weed control in field-grown Korean boxwood (Buxus microphylla Siebold & Zucc. ‘Koreana’) and Photinia (Photinia × fraseri) at Belle Mina, Ala., over a 3-year production period. Treatments were applied twice during each growing season. Greatest control of the annual grass and broadleaf weed species was with oryzalin tank-mixed simazine at rates of either 2.2 + 0.8 or 3.4 + 1.1 kg a.i. per ha−1, respectively. These treatments were not injurious to either species and consistently resulted in the highest growth indices. No injury was detected when additional liners of boxwood were planted in the treated plots at the termination of the experiment. Chemical names used: 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin); 6-chloro-N,N’-diethyl-1,3,5-triazine-2,4-diamine (simazine); and 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor).
Abstract
Artificial infestation with egg masses to simulate severe natural second brood European corn borer, Ostrinia nubilalis (Hubner), infestation caused less stalk and stalk-associated damage in the resistant field corn inbred ‘B52’ Zea mays L. than in susceptible sweet corn inbreds. Relatively severe damage, however, occurred on and around the region of the primary ear in both ‘B52’ and the sweet inbreds. Because direct kernel damage is of paramount economic importance in sweet corn as opposed to field corn, forms of second-brood resistance in addition to that found in ‘B52’ should be sought in sweet corn improvement. For stalk tunneling and number of sheath and collar lesions the resistance of F1 and F2 progenies was intermediate between the resistance of ‘B52’ and the sweet inbreds. Although there were no parental differences in damage to the ear, F1 and F2 means showed some indication of resistance.
This study reports on the performance of 34 clones of crapemyrtle (Lagerstroemia indica L., L. fauriei Koehne, and L. indica × L. fauriei hybrids) grown in field plots at four locations representative of different environments in the southeastern United States. Traits evaluated were spring leaf-out and initiation of flowering in the second season after field planting and plant height after 3 years of growth. Cluster analysis (Ward's method) was used for grouping and comparison of means across locations for each trait. Best linear unbiased prediction was used for estimating random effects in linear and generalized linear mixed models to better determine the general performance of the clones under a variety of environmental conditions. Each clone's trait stability was quantified using the regression of an individual genotype's performance for each of the three studied traits on an environmental index based on the trait mean for all genotypes grown in an environment. Sequence of clone leaf-out and size rankings were more stable across the environments than the sequence in which the various clones initiated flowering. L. fauriei clones and clones originating from the initial cross between L. indica and L. fauriei were generally later to leaf out, earlier to flower, and more vigorous growers than L. indica or the complex L. indica × L. fauriei clones that were evaluated. First flowering was affected by environmental variation more with interspecific hybrids than with L. fauriei and L. indica clones. Performance, particularly with respect to plant height, of several clones did not agree with previously published classifications. Information generated by this study will allow crapemyrtle breeders, landscape professionals, and consumers to better select the most appropriate crapemyrtle clone for a particular application.