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Elizabeth T. Maynard

Three nitrogen sources applied through drip irrigation were compared to preplant-applied urea to evaluate their effects on tomato (Lycopersicon esculentum Mill.) and bell pepper (Capsicum annum L.) earliness, yield, and blossom end rot (BER) in 1995 and 1996. Calcium nitrate (CaNO3), urea ammonium nitrate (UAN), and ammonium nitrate (NH4NO3) were applied at 11.2 kg N/ha weekly beginning 2 weeks after transplanting for a total of 8 weeks. The urea treatment received 112 kg N/ha before planting and fertigated treatments received 22.4 kg N/ha from urea before planting. In 1995 only, two additional treatments were fertilized with chicken manure only (1.3N–0.7P–0.8K) at 112 kg N/ha and 168 kg N/ha. In 1996, nitrogen treatments were compared at two levels of potassium fertilization: 0 or 269 kg K/ha. `Sunrise' or `Mountain Spring' tomatoes and `Ranger' peppers were transplanted into black plastic in mid to late June each year. Nitrogen treatments had no effect on marketable or total yield, fruit size, or BER of tomatoes. Total pepper yield was lower with urea than with CaNO3; early and marketable yields showed similar trends, but differences were not consistently significant. UAN and NH4NO3 pepper yields were usually similar to yield with CaNO3, but did not always differ from urea yields. Compost treatments produced yields intermediate between urea and fertigated treatments in 1995. In 1996, peppers from UAN and NH4NO3 plots had more BER (0.5% to 1%) than CaNO3 plots (0%); urea plots had an intermediate amount of BER (0.2%).

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Elizabeth T. Maynard*

In northern Indiana, jack-o-lantern pumpkins (Cucurbita pepo) can be planted from late May through June to produce mature fruit for sales associated with Halloween. Field trials were conducted to evaluate the influence of planting date on pumpkin yield and yield components. `Gold Medal' and `Magic Lantern' pumpkins were each seeded on three planting dates (PD) in 2002 (31 May, 10 and 20 June 10) and 2003 (5, 16, and 25 June). Each planting date was harvested between 100 and 110 days after planting. The weight per plant of pumpkins that were completely mature (orange) was greatest for the June 10 planting in 2002 (14.9 kg vs. 12.5 kg for 1st and 12.2 kg for 3rd PD), but did not differ among dates in 2003 (PD1: 10.9 kg, PD2: 10.4 kg, PD3: 9.0 kg). The number of orange pumpkins per plant was lowest for the 20 June 2002 planting (1.63 vs. 1.88 for 1st and 1.91 for 2nd PD) but did not differ among dates in 2003 (PD1: 1.08, PD2: 1.20, PD3: 1.19). The average weight of an orange pumpkin was lowest for the 31 May 200 planting date (7.17 kg vs. 8.35 kg for 2nd and 7.89 kg for 3rd PD) and highest for the 5 June 2003 planting date (10.6 kg vs. 9.07 kg for 2nd and 8.16 kg for 3rd PD). In both years the last planting date produced the least weight per plant, and in 2002 the fewest number, of pumpkins that had begun to turn orange plus fully orange pumpkins. The two cultivars produced similar weight per plant and responded similarly to planting date, but `Gold Medal' produced fewer and larger fruit. No planting date consistently produced the greatest yield or largest fruit.

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Elizabeth T. Maynard

Benefits of drip irrigation for jack-o-lantern pumpkins (Cucurbita pepo) in the midwestern United States are not documented. Field trials were conducted on a sandy loam soil to compare yield and fruit size of unirrigated pumpkins (NONE) with pumpkins irrigated when in-row soil water tension (SWT) 30 cm deep reached 20 kPa (HIGH) or 60 kPa (MED). The 2004 trial included two planting methods, direct seed (SD) and transplant, and two cultivars, `Gold Medal' (GM) and `Magic Lantern' (ML). GM typically has larger and more vigorous vines than ML. In 2005 the trial included only SD ML. Rainfall June through August totaled 38.4 cm in 2004 and 28.2 cm in 2005. In 2004 HIGH increased yield 13% compared to NONE (42.1 vs. 37.2 t·ha-1). MED (39.0 t·ha-1) did not differ from NONE. Neither planting method nor cultivar influenced the yield response to irrigation. The effect of irrigation on average weight per pumpkin depended on cultivar. In 2004, ML with HIGH averaged 7.76 kg per pumpkin, 16% heavier than NONE at 6.67 kg. MED averaged 7.17 kg. Irrigation did not affect average weight of GM: HIGH, MED and NONE averaged 12.6, 12.8 and 12.3 kg, respectively. For SD ML, combined analysis of 2004 and 2005 data showed an 18% increase in average pumpkin weight for HIGH vs. NONE (7.94 vs. 6.72 kg), but no significant effect of irrigation on yield (33.6, 29.8 and 28.4 t·ha-1 for HIGH, MED and NONE, respectively). Irrigation did not affect the number of pumpkins produced per hectare for either cultivar in either year. Results suggest that compared to no irrigation, maintaining SWT less than 20 kPA with drip irrigation may lead to 1) yield increase on the order of 10% or less, 2) 16% to 18% increase in average pumpkin weight for ML.

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Elizabeth T. Maynard

In a wet spring, transplants must often be held beyond the planned transplant date. The plants become overgrown, making mechanical transplanting difficult. We compared several ways of holding `Mountain Spring' tomato (Lycopersicon esculentum L.) transplants. Transplants were 1) planted outside on planned transplant date in late May (NH), 2) held outside for 2 weeks (HOF), 3) held outside for 2 weeks and not fertilized during that period (HONF), and 4) held in the greenhouse for 2 weeks (HGF). Throughout transplant production, half of the transplants in each holding treatment were fertilized with 100 ppm N and half with 25 ppm N from 20N-4.4P-17K or 15N-2.2P-12.3K. HONF reduced plant height 1.7 to 1.5 cm compared to HOF or HGF. Plants grown with 25 ppm N were 5 to 6.4 cm shorter than plants grown with 100 ppm N and showed symptoms of nutrient deficiency. On average, holding treatments reduced marketable yield 20% to 23% and early yield 31% to 37%, compared to NH. HOF and HGF produced similar marketable yield, early yield, and fruit size. HONF decreased early yield in 1997 and decreased marketable yield in 1998, compared to HOF. The differences between holding treatments were usually greater with 100 ppm N. Plants grown at 25 ppm N produced lower marketable and early yields and larger fruit than 100 ppm N. The best method for holding transplants among those tried here is to put them outdoors and continue fertilizing as during transplant production.

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Elizabeth T. Maynard

This experiment was conducted to determine whether light conditions during cultivation affect the number or species composition of emerging weeds. Plots were cultivated on 31 May 1996 under the following light conditions: 1) Ambient nighttime light (full moon) plus tractor headlights, 2) ambient nighttime light plus tractor headlights covered by transparent green film (green tractor lights), 3) ambient nighttime light with no tractor headlights, 4) ambient mid-day light. A fifth treatment was not cultivated at all, but was treated with glyphosate on 31 May to kill emerged plants. Results discussed below are based on weed densities determined 3 weeks after cultivation. Cultivated plots had more broadleaf weeds than uncultivated plots (119/m2 vs. 40/m2). Annual grass populations were the same in cultivated and uncultivated plots (20/m2). Common lambsquarters (Chenopodium album) and carpetweed (Mollugo verticillata) were the most common annual broadleaf weeds, representing more than 80% of the annual broadleaf population in cultivated plots. Light conditions during cultivation did not influence the total number of broadleaves, number of annual grasses, or total number of weeds emerging. Lambsquarters emerged in greater numbers after daytime or night cultivation using green tractor lights (48/m2) than after night cultivation using standard tractor headlights (32/m2). These results suggest no practical benefit to night cultivation for reducing overall weed density. A similar study in 1995 led to a similar conclusion. Although measurable effects of light conditions on weed emergence were observed in both years, the magnitude and consistency of the effects were not enough to suggest changes in cultivation practices without further research.

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Elizabeth T. Maynard, Charles S. Vavrina and W. Dennis Scott

Muskmelon (Cucumis melo L. cvs. Superstar and Mission) transplants were grown in cellular seedling trays of polystyrene or styrofoam, with individual cells ranging in volume from 7 to 100 cm3, transplanted to the field, and grown to maturity in Florida and Indiana during the 1993 and 1994 growing seasons. Seedling leaf area, shoot and root weights before transplanting, and shoot dry weight 20 days after transplanting increased linearly with increasing cell volume in Florida. Thirty days after transplanting, vine length showed significant linear and quadratic trends with respect to cell volume in Indiana. In Florida, early and total yields increased linearly as transplant cell volume increased for `Mission' in both years and for `Superstar' in 1994. In Indiana, early yields increased linearly as transplant cell volume increased for `Mission' in 1994 and for `Superstar' in both years, but cell volume did not consistently affect total yield. Transplant tray effects on early and total yield unrelated to linear or quadratic effects of cell volume occurred in both locations, but these effects were not consistent.

Open access

Ahmad Shah Mohammadi, Elizabeth T. Maynard, Ricky E. Foster, Daniel S. Egel and Kevin T. McNamara

Bacterial wilt of cucurbits, incited by Erwinia tracheiphila (E. F. Smith) and vectored by the striped cucumber beetle [Acalymma vittatum (F.)] (SCB), is a serious disease of muskmelon (Cucumis melo L.). Cultivars differ in attractiveness to SCB and susceptibility to bacterial wilt, but no cultivar resistant to bacterial wilt has been introduced. In 2015 and 2016, replicated field plots of eight cultivars were grown at Lafayette, Wanatah, and Vincennes, IN, to identify differences in attractiveness to SCB and susceptibility to bacterial wilt. ‘Savor’ had significantly more beetle activity than ‘Hales Best’, ‘Superstar’, and ‘Aphrodite’ in three of six site-years, and more than ‘Diplomat’, ‘Dream Dew’, ‘Athena’, and ‘Wrangler’ in two site-years. Beetle activity for ‘Athena’, ‘Superstar’, and ‘Wrangler’ did not differ significantly from ‘Aphrodite’ for any site-year. Bacterial wilt severity was significantly greater for ‘Diplomat’ and ‘Dream Dew’ than for other cultivars in four site-years. ‘Superstar’ had the least disease in five site-years, but significantly less than ‘Aphrodite’, ‘Athena’, and ‘Hales Best’ in only one site-year. At one site, additional plots of each cultivar were populated with five SCBs per plant, and rowcovers were applied to keep the SCBs near the plants for 3 weeks. This resulted in similar beetle activity on all cultivars, but most disease in ‘Dream Dew’ and least in ‘Superstar’ and ‘Athena’. Marketable yield was generally highest for ‘Aphrodite’, ‘Superstar’, and ‘Athena’ when plants were exposed to natural beetle populations. Overall, ‘Savor’ and ‘Diplomat’ were the most attractive to beetles, and ‘Diplomat’ and ‘Dream Dew’ were the most susceptible to bacterial wilt. ‘Aphrodite’, ‘Athena’, and ‘Superstar’ were less attractive to beetles and showed more tolerance to bacterial wilt in both 2015 and 2016.

Open access

Analena B. Bruce, Elizabeth T. Maynard and James R. Farmer

High tunnels are an increasingly popular part of the infrastructure among small and diversified farms that market their products directly to consumers. In addition to extending the growing season, research has strongly indicated that high tunnels can increase yield, enhance shelf life, and improve the quality of crops grown. The objective of this study was to gain a better understanding, from the perspective of farmers, of the challenges and opportunities associated with adopting high tunnels for specialty crops in Indiana. We collected information through a case study that included questionnaires and in-depth interviews with 20 farmers. We found that the additional labor and time requirements of high tunnel production, the increased complexity of high tunnel production, soil fertility, and disease management, and limited winter markets posed the greatest challenges. The ability to differentiate their products based on higher quality and longer shelf life, the ability to obtain a premium price, the ability to have a source of income during the off-season, and the ability to produce complementary crops were the most important opportunities for using high tunnels. This research implied ways to expand opportunities and reduce barriers to maximizing the potential of high tunnels. Understanding the human dimensions of managing high tunnels is important for providing extension educators and Natural Resources Conservation Service field staff with better knowledge of the common difficulties and benefits of this technology so they are better able to advise farmers considering investing in a high tunnel. A focus on the human dimensions is also helpful for identifying research priorities to evaluate new approaches to decreasing problems and increasing benefits. Consequently, this study provided an in-depth understanding of farm-level challenges associated with high tunnel adoption to improve future research in diverse fields.