Eighty-two vegetable growers responded to a survey on pests, beneficial insects, and cover crop use sent in Winter 1993–94 to 314 members of the Virginia Assn. for Biological Farming (VABF) and participants at the 1993 Virginia Sustainable Agriculture Conference. Respondents reported 68 occurrences of insect pests on 99 vegetable crops and herbs. Six insects (flea beetle, squash vine borer, stink bug, cucumber beetles, and Mexican bean beetle) comprised 70% of the occurrences. Squash vine borer and cucumber beetles on cucurbits comprised 24% of all pest occurrences. Insect pests attacked summer squash on 57% and cucumber on 49% of the farms. Average severity of squash vine borer damage was 3.8 (range 0–4, where 0 = no damage and 4 = death or destroyed). Average severity of cucumber beetle damage was 3.0 (severe). Squash vine borer was not observed by farmers on non-cucurbit alternate hosts. Cucumber beetles were observed on horse nettle (10%) and wild nightshades (6%), but on no other plants in most cases (61%) when found on cucurbits. The most frequently observed beneficial insects were lady beetles (64% of the farms), preying mantises (42%), wasps (29%), assassin bugs (18%), and spiders (15%). Only 29% of the farms had purchased beneficial insects, with assassin bugs (10%) and lady beetles (7%) the most common types. Vetches, clovers, rye, and buckwheat comprised 69% of the responses on 23 types of cover crops and mulches used.
J.S. Caldwell, J.P. Amirault, and A.H. Christian
Christian A. Wyenandt, Landon H. Rhodes, Richard M. Riedel, and Mark A. Bennett
The development of septoria leaf spot in processing tomatoes grown on conventional (bare soil) beds or beds with chemically or mechanically killed winter rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth) cover crop mulch with or without fungicide was examined. The two fungicide treatment programs included fungicide applied weekly (7 d) and a no fungicide control. In mulch bed systems without fungicide, septoria leaf spot caused ≈50% defoliation 10 and 28 d later in 1997 and 1998 than in the conventional system, respectively. In both years, area under disease progress curve (AUDPC) values for septoria leaf spot development were lower with the presence of a chemically or mechanically killed mulch compared with the conventional bed system when no fungicide was applied. In 1997, there were no significant differences in AUDPC values for septoria leaf spot development when fungicide was applied weekly. In 1998, AUDPC values were lower in both mulch systems compared with the conventional bed system when fungicide was applied weekly. At harvest in both years, defoliation was highest in the no fungicide control treatment. In 1997, marketable yield was significantly higher in both mulch systems compared with the conventional bed system. Conversely, in 1998, marketable yield was significantly higher in the conventional bed system than in either mulch bed system.
Christian A. Wyenandt, Landon H. Rhodes, Mark A. Bennett, and Richard M. Riedel
The effects of three bed systems [conventional (bare soil), chemically killed, or mechanically killed winter rye (Secale cereale) + hairy vetch (Vicia villosa) cover crop mulch] and five fungicide programs (no fungicide, 7-day fungicide application program, and Tom-Cast-timed fungicide applications at 15, 18, or 25 disease severity values) on marketable yield and soil-borne fungal fruit rot development in processing tomato (Solanum lycopersicum) production were studied. In 1997, marketable yield was higher in both cover crop systems compared with the conventional bed system. In 1997, percentage of anthracnose- (Colletotrichum coccodes) and ground rot-infected fruit (caused by Pythium spp. or Phytophthora spp.) were lower in both cover crop mulch systems compared with the conventional bed system. In 1998, marketable fruit yields were lower in both cover crop mulch systems compared with the conventional bed system. Percentage of anthracnose-infected fruit was lower in 1998 in the chemically killed cover crop mulch system compared with mechanically killed bed system. There were no differences in ground rot-infected fruit between bed systems in 1998. In 1998, percentage of total molded fruit in the chemically killed cover crop mulch system was reduced compared with the mechanically killed cover crop mulch system.
Christian A. Wyenandt, Richard M. Riedel, Landon H. Rhodes, Mark A. Bennett, and Stephen G.P. Nameth
In 2001 and 2002, fall- and spring-sown, spring-killed or spring-sown living cover crops mulches were evaluated for their effects on pumpkin (Cucurbita pepo) number and weight, fruit cleanliness, and fusarium fruit rot (FFR; Fusarium solani f. sp. cucurbitae race 1). In general, the number and weight of orange (mature) fruit and total fruit weight were higher in bare soil (conventional), fall- or spring-sown, spring-killed cover crop mulches compared with spring-sown, living annual medic (Medicago spp.) cover crop mulches. In both years, pumpkins grown on fall-sown winter rye (Secale cereale), hairy vetch (Vicia villosa), winter rye + hairy vetch, and spring-sown oat (Avena sativa) produced fruit numbers and weights comparable to or slightly higher than bare soil (conventional) production, suggesting that these cover crop mulches had no effects on reducing pumpkin yield. The number and weight of pumpkins grown in spring-sown, living annual medic cover crop mulches were reduced in both years compared with the other cover crop mulches. On artificially inoculated field plots, percentages of groundcover at harvest and fruit with FFR were 89% and 5% in fall-sown winter rye (seeded at 90 lb/acre), 88% and 10% in fall-sown rye (50 lb/acre), 85% and 5% in fall-sown rye + hairy vetch (50 lb/acre each), 19% and 30% in fall-sown hairy vetch (50 lb/acre), 23% and 23% in spring-sown oat (110 lb/acre), 1% and 25% to 39% in spring-sown, living annual medics (40 lb/acre) and 0% and 46% in bare soil plots, respectively. Results suggest that cover crop mulches such as fall-sown winter rye, fall-sown winter rye + hairy vetch, or spring-sown, spring-killed oat killed and left on the soil surface may help reduce losses to FFR in pumpkin production.
Gregg C. Munshaw, Jeffery S. Beasley, Christian M. Baldwin, Justin Q. Moss, Kenneth L. Cropper, H. Wayne Philley, Chrissie A. Segars, and Barry R. Stewart
Hybrid bermudagrass [Cynodon dactylon × Cynodon transvaalensis] is frequently used throughout the southern and transitional climatic zones of the United States. These grasses can only be vegetatively propagated, such as by sprigging. Turf managers will often apply high rates of sprigs and nitrogen (N) in an attempt to minimize the time to establishment. However, little is known about how planting and N rates affect establishment. The objective of this study was to determine optimum sprigging and N rates during the establishment of ‘Latitude 36’ hybrid bermudagrass to minimize time to full surface cover. The study was conducted in four locations across the southern United States during Summer 2015. Sprigging rates consisted of 200, 400, 600, and 800 U.S. bushels/acre (9.3 gal/bushel), and N rates were 0, 11, 22, and 44 lb/acre N per week. Results showed that as the N rate increased, percent cover generally increased but only slightly [7% difference between high and low rates 5 weeks after planting (WAP)]. The effect of sprig rate on percent cover indicated that as rate increased, cover also increased. Differences in establishment due to sprig rate were present until 6 WAP at which time all plots achieved 100% cover. The greatest difference between N and sprig rate was that sprig rate showed differences in percent cover immediately, whereas N rate differences were not apparent until 2 WAP. Increasing sprig rather than N rate should be considered to speed up establishment.