Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Mark Davis x
Clear All Modify Search

Small-scale research plots and demonstrations of fertilizer application through a drip-irrigation system have inherent characteristics that make using commercial fertilizer injection systems difficult. Uniform fertilizer application, without excessive water, is essential for meaningful results in these small-scale, rate-specific studies. An inexpensive, easy to build, continuously diluting fertilizer injector is described. This injection system was reliable and provided uniform application under the confines of a low flow rate.

Full access

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.

Open Access

Seed germination patterns were studied in Echinacea purpurea (L.) Moench grouped by seed source, one group of seven lots from commercially cultivated populations and a second group of nine lots regenerated from ex situ conserved wild populations. Germination tests were conducted in a growth chamber in light (40 μmol·m–2·s–1) or darkness at 25 °C for 20 days after soaking the seeds in water for 10 minutes. Except for two seed lots from wild populations, better germination was observed for commercially cultivated populations in light (90% mean among seed lots, ranging from 82% to 95%) and in darkness (88% mean among seed lots, ranging from 82% to 97%) than for wild populations in light (56% mean among seed lots, ranging from 9% to 92%) or in darkness (37% mean among seed lots, ranging from 4% to 78%). No germination difference was measured between treatments in light and darkness in the commercially cultivated populations, but significant differences were noted for treatments among wild populations. These results suggest that repeated cycles of sowing seeds during cultivation without treatments for dormancy release resulted in reduced seed dormancy in E. purpurea.

Free access

Afield study of organic production of tomato (Lycopersiconesculentum Mill.) in high-tunnels was conducted in 2004. `Mountain Fresh' was transplanted 31 Mar.; `Ultra Sweet' and `Sun Leaper' were transplanted on 21 July. The primary objective was to determine the feasibility of obtaining two crops of fresh-market tomatoes by starting plants 4–8 weeks earlier than the average last spring-killing frost, and extending the growing season 4–6 weeks past the average first fall-killing frost. Plants were started at weekly intervals for 4 weeks in both seasons. Data and observations were recorded on the yield of marketable fruits, plant growth and development, and plant health. Other objectives were to evaluate: 1) the benefits of using a selective UV-blocking film on plant growth and development, disease events; and 2) compost amendments on soil improvement and disease control. Major cultural challenges included water management, soil texture/drainage, prevention of chilling injury, plant support, and adequate ventilation. Major disease/pest challenges involved stalk rot caused by Sclerotinia sclerotiorum in the spring, powdery mildew in spring and late summer, Alternaria and Septoria leaf blight in late summer, and aphids, tomato hornworm, corn earworm, and beet army worm also in late summer. In addition, macrofaunal intrusions by fox, mice, and birds occurred sporadically. Poor drainage and stalk rot in the spring necessitated relocating the tunnels to an uninfested site with better drainage. The fall crop yielded high numbers of marketable quality fruits, well beyond the 15 Oct. average killing frost date. The results suggest that with improved management, there is a considerable potential for profitable extended-season production of organic tomatoes in this region.

Free access