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David A. Bender, William P. Morrison, and Raymond E. Frisbie

A system of intercropping cabbage (Brassica oleracea var. capitata L.) with Indian mustard [Brassica juncea (L.) Czern.] to reduce pesticide applications was evaluated over three cropping seasons. Insects were monitored in nonintercropped cabbage, cabbage plots surrounded by Indian mustard, and the Indian mustard intercrop. Insecticide applications were made to individual plots based on specific treatment thresholds for lepidopterous insects and accepted pest management practices for other insects. Intercropping had no significant effect on the number of lepidopterous larvae in cabbage. Indian mustard did not appear to preferentially attract lepidopterous insects, but was highly attractive to hemipterans, especially harlequin bugs [Murgantia histrionica (Hahn)]. In one season with heavy harlequin bug pressure, intercropping with Indian mustard eliminated two insecticide applications to cabbage. Intercropping cabbage with Indian mustard does not appear to be an economical pest management practice under normal pest pressures in West Texas.

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David A. Bender and William P. Morrison

Indian mustard (Brassica juncea) has been reported to be a preferred host for diamondhack moth (Plutella xylostellu) and other insect pests when interplanted with cabbage (Brasssica oleracea var. capitata). A cabbage-Indian mustard companion planting study was conducted to determine the seasonal occurrence of cabbage insects and the potential for using a trap-crop system to reduce insecticide applications to cabbage in West Texas. Three-row plots of cabbage 9 m long were transplanted with and without sequentially seeded borders of Indian mustard in three seasons. Harmful and beneficial insects were counted at roughly weekly intervals. Insecticides were applied when insect populations in individual plots reached predetermined thresholds. Indian mustard did not appear to be more attractive than cabbage to lepidopterous pests, but did preferentially attract hemipterans, particularly harlequin bugs (Margantia histrionica). The mustard trap crop eliminated two insecticide` applications in one trial by reducing harlequin bug pressure on the cabbage.

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David A. Bender and William P. Morrison

Indian mustard trap crops have successfully reduced pesticide use on commercial cabbage in India. Diamondback moth has been a serious pest of cabbage in Texas and has demonstrated resistance to most classes of insecticides. Use of a trap crop could fit well in an integrated management program for cabbage insects, Three-row plots of spring and fall cabbage were surrounded by successive single-row plantings of Indian mustard in trials at Lubbock, Texas to determine the efficacy of interplanting for reducing insecticide applications. Insects in the cabbage and Indian mustard were counted twice weekly, and insecticides were applied selectively when economic thresholds were reached. Indian mustard was highly attractive to harlequin bugs, and protected intercropped spring cabbage. Cabbage plots without mustard required two insecticide applications to control the infestation. False chinch bugs were also highly attracted to Indian mustard. Lepidopterous larvae, including diamondback moth, did not appear to be attracted to the trap crop. Indian mustard trap crops reduced insecticide applications to spring cabbage but had no positive effect on fail cabbage.

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Ed Stover and William Castle

Sour orange (Citrus aurantium) has been the dominant citrus rootstock in the Indian River region of Florida since the initial plantings in the 1880s. Use of this rootstock in new plantings has been rare since 1990 because of heightened concern about decline strains of citrus tristeza virus (CTV), to which this rootstock is highly susceptible. Because the proportion of trees remaining on sour orange rootstock and the rate of decline among them are important in predicting the economic consequences for the Indian River citrus industry, two surveys of rootstock usage were conducted for citrus in this growing region. In the first survey, growers were asked about rootstock usage and problems observed across all types of citrus, and responses represented 35% of acreage. In the second survey, growers were restricted to rootstock usage and grower observations on decline for grapefruit (C. paradisi), and responses represented 53% of acreage. Even though 44% of all current Indian River grove area has been planted since 1987, when use of sour orange for new plantings largely ceased, 48% of all citrus and 55% of all grapefruit grove area are currently on sour orange rootstock. The percentage of grapefruit trees on sour orange rootstock that showed significantly health decline in 2000 was 8% based on grower reports. The other root-stocks representing substantial commercial grove area have known problems and limitations that are likely to prevent any of them from gaining the prominence once held by sour orange. Swingle citrumelo (C. paradisi × Poncirus trifoliata) at about 25% of grove area, Cleopatra mandarin (Citrus reticulata) at about 8%, and Smooth Flat Seville (Citrus hybrid) at about 3% all represented similar acreage for grapefruit and across all cultivars, while Carrizo citrange (C. sinensis × P. trifoliata) use was reported for 4% of grapefruit and 13% overall. Evaluation and development of new rootstocks is vitally important for the Indian River area, especially for soils with significant clay and calcium content.

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Ed Stover, Dominick Scotto, and James Salvatore

Pesticide spray practices for citrus (Citrus spp.) in the Indian River region of Florida were surveyed in 2001 as the first step in identifying opportunities for improving efficiency and reducing potential environmental impact. The survey covered 73% of grapefruit (C. paradisi) acreage in Indian River, St. Lucie, Martin and Palm Beach counties, comprising 70% of all Indian River commercial grapefruit. Large differences in spray practices were revealed. The focus of this survey was grapefruit spraying, since grapefruit represent 59% of fresh citrus shipped from the Indian River region, and are sprayed more intensively than citrus fruit grown for processing. In commercial groves, almost all foliar sprays to grapefruit are applied using air-assisted sprayers pulled through the groves by tractors. Use of engine-driven and power-takeoff-driven sprayers were reported with equal frequency and accounted for 89% of spray machines used. Lowvolume Curtec sprayers comprised the remainder. Spray volume for grape-fruit varied: 7.6% of acreage was sprayed at 25 to 35 gal/acre (230 to 330 L·ha-1) for all sprays; 4.2% was sprayed at 100 to 170 gal/acre (940 to 1600 L·ha-1) for all sprays; 15.3% was sprayed at 200 to 380 gal/acre (1900 to 3600 L·ha-1) for all sprays; 28.2% was sprayed at 450 to 750 gal/acre (4200 to 7000 L·ha-1) for all sprays; and 44.5% of grapefruit acreage was sprayed in a progressive manner from lower to higher volume as the season progresses. Many mid and high spray volume growers reported unacceptable results when they lowered spray volume. Although correlation was moderate (r = 0.35 to 0.45), regressions indicated that both total foliar pesticide spray material costs, and annual fungicidal copper (Cu) use increased with spray volume used for postbloom fungicides. Mean Cu use per acre was in the middle of the recommended range. All growers reported adjusting nozzling for tree height within a grove, and since Indian River groves are bedded, growers adjusted sprayer output differently for trees on bed tops versus furrows on 85% of acreage. Sprayers were shut off for missing trees on 83% of acreage, but this was done only for two or more adjacent trees on almost half of this area. Sensor-actuated sprayers were used to minimize off-target application on 14.7% of grapefruit acreage, but for an additional 21% of acreage, growers reported trying and abandoning this technology. While 88% of grove acreage was sprayed during the day, 75% of acreage sprayed using less than 100 gal/acre was sprayed at night. Growers reported no defined protocol for ceasing spray operations based on environmental conditions.

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Chris Wilson, Ed Stover, and Brian Boman

Off-target deposition of pesticidal spray material is both an economic loss to the grower and a potential environmental problem in southern Florida. This study evaluated the reduction in non-target deposition of copper resulting from different approaches to spraying row-ends in typical Indian River citrus (Citrus) production systems. Using copper as a model pesticide, applications were made in a commercial citrus grove in June and July 2001. Non-target deposition on the water surface within an adjacent drainage canal, as well as on surrounding ground surfaces, was measured using Teflon spray targets. Specific row-end spraying scenarios included: 1) leaving both banks of nozzles on while turning; 2) turning the outside-facing nozzles off (leaving tree-facing nozzles on); 3) turning both banks of nozzles off at the tree trunk; and 4) turning all nozzles off at the end of the foliage of the last tree within the row. Deposition directly onto surface water contained within drainage canals was reduced significantly when nozzles were turned off at the last tree within a row, or when the outside-facing nozzles-only were turned off through the turn. Likewise, deposition was reduced on ground surfaces adjacent to the sprayer under the same scenarios. No differences were observed on ground surfaces on the opposite side of the canal. Significant reductions in direct application of agrichemicals to surface waters within Indian River citrus production groves can be achieved by turning nozzles off when turning from one tree row into the next.

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Pamela Borden

Indian Paintbrush (genus Castilleja) is a group of attractive wildflowers in which some species are facultative parasites on native grasses during early growth. This study hopes to characterize optimum germination, cultural and host requirements of several species. Lots of 100 seed of wild-collected Castilleja coccinea (L.) Spreng. produced 22% germination without pre-treatment or presence of host plants 10 days after seeding at 21°C with 12 hours light. Seed soaked 24 hours in distilled water, 10 mg/l GA3 or-post-plant treated with Regal Crown nutrient and growth regulator soluotion did not significantly differ from above. Moist stratification at 4°C for 20 days significantly increased germination to 46%. Further stratification (up to 80 days) did not further increase germination. Additional data on light, temperature, media and presence of host plants will also be presented for this and other species.

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Hongyi Zhang, William R. Graves, and Alden M. Townsend

Single-node cuttings of `Autumn Flame' and `Indian Summer' red maple (Acer rubrum L. and A. × freemanii E. Murray) were placed in subirrigated perlite that was kept at 29, 33, or 36 C at the cut ends for 3 weeks. Number and mass of roots and pigment quality and transpiration of leaves were greater for `Autumn Flame' than `Indian Summer' and decreased with increasing temperature for both cultivars. Rooting percentage at 29, 33, and 36 C was 75, 75, and 25 for `Autumn Flame' and 13, 13, and 0 for `Indian Summer'. Earlier work has shown > 90% of cuttings of both cultivars root at ≈ 22 C, and plants of `Autumn Flame' are more heat resistant than those of `Indian Summer'. Results of this experiment suggest the effect of heat on rooting of cuttings might be used to predict genotypic differences in heat resistance of whole plants.

Open access

K. V. Peter, R. W. Goth, and R. E. Webb

Abstract

The 4 hot peppers from India ‘Pant C-1’, ‘KAU Cluster’ (Capsicum annuum L.), ‘White Khandari’, and ‘Chuna’ (C. frutescens L.) were evaluated along with 6 United States cultivars for their reaction to Pseudomonas solanacearum E.F. Smith (races 1 and 2), Phytophthora capsici Leonian, and root-knot nematode Meloidogyne incognita Chitwood. The Indian ‘Pant C-1’ was resistant to 4 Pseudomonas solanacearum isolates and moderately resistant to Phytophthora root rot and root-knot nematode. The breeding line ‘White Khandari’ was resistant to 3 isolates of the bacterium and root-knot nematode and moderately resistant to Phytophthora root rot. These Indian pepper lines could be an additional source in multiple disease-resistant breeding programs. Multiple disease resistance and good horticultural characteristics make ‘Pant C-1’ an excellent source of these resistances.

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Rick Gibson, Everett Rhodes, and Marshall Sunna

An educational attempt to assist Gila River Indian Community members to return to a sustainable small-farm heritage has shown initial success after 1 year. The project uses horticultural technology to help tribal members overcome severe social concerns. The first phase addressed the needs of youth at risk through a 10-acre farm at the Gila River Indian Community Juvenile Rehabilitation and Detention Center in Sacaton, Ariz. During 1993, the farm operation leveled 10 acres of squash, corn, and watermelons; planted and cared for 200 deciduous fruit and citrus trees; and planted and cared for 150 commercial Christmas trees. Produce was either sold to community members or donated to community food centers at the schools or at homes for the elderly. The youth were led by 14 volunteers who completed an intensive training program and were certified as Master Gardeners by the Univ. of Arizona. They have donated -300 hours of time to the project. The project gave youth at risk an opportunity to learn new concepts and skills, gain exercise, and work off detention time. As tribal leadership observed the initial successes, they gave permission to address health and nutrition as well as other youth-at-risk targets within the community beginning in 1994.