Powdery mildew in euonymus (Euonymus japonica Thunh.) plants, caused by Oidium euonymi-japonica (Arcang.) Sacc., was controlled by applying various polymer coatings or an aqueous solution of sodium or potassium bicarbonate plus horticultural Sun Spray (SS) Ultra Fine Oil 1% (v/v) to plant foliage. The combined treatment (bicarbonate + oil) was more effective than either of the two materials alone. The results indicate that sodium or potassium (but not ammonium) bicarbonate solutions mixed with SS seems to be a useful biocompatible fungicide for controlling powdery mildew in euonymus plants. Some of the polymer coatings effectively reduced disease levels when applied immediately after the symptoms first appeared.
O. Ziv and A. Hagiladi
Carey Grable, Joshua Knight, and Dewayne L. Ingram
with a wider range of release rate. The objective of this study was to determine the effects of four formulations of CRF, including two with new polymer coating technology, on leachate pH and electrical conductivity (EC), and plant growth of two species
Raul I. Cabrera
Seven nursery grade (8-9 month duration), polymer-coated, controlled-release fertilizers (CRF) were topdressed or incorporated into a 2 peat: 1 vermiculite: 1 sand (by volume) medium to yield the same amount of N per container. The pots (0.5 L) were uniformly irrigated with DI water every week to produce a target leaching fraction of 25%. Leachate N contents (ammonium plus nitrate), employed as indicators of N release, allowed for comparison of CRF performance as a function of temperature changes over a season. Two distinct N leaching (i.e., release) patterns were observed over the 180-day experimental period. The fertilizers Osmocote 18-6-12FS (Fast Start: OSM-FS), Prokote Plus 20-3-10 (PROK), Osmocote 24-4-8HN (High N: OSM-HN) and Polyon 25-4-12 (POLY) exhibited a N leaching pattern that closely followed changes in average daily ambient temperatures (Tavg) over the season. This relationship was curvilinear, with N leaching rates per pot (NLR) being highly responsive to Tavg changes between 20 and 25 °C. Temperatures above 25 °C produced an average maximum NLR of 1.27 mg·d-1 for these fertilizers. OSM-FS, PROK, and OSM-HN had the highest cumulative N losses over the experimental period. In contrast, the CRF group formed by Nutricote 18-6-8 (270: NUTR), Woodace 20-4-12 (WDC), and Osmocote 18-6-12 (OSM) showed a more stable N leaching pattern over a wider range of temperatures, with rates about 30% to 40% lower than those in the temperature-responsive CRF, and averaging a maximum NLR of 0.79 mg·d-1 for Tavg >25 °C. NUTR and WDC had the lowest cumulative N losses over the season. Soluble salt readings paralleled N leaching for each CRF, indicating similar leaching patterns for other nutrients. Incorporation produced significantly higher cumulative N losses than topdressing, but without effect on the actual N leaching pattern over the season. Regardless of the N formulation in the CRF, over 85% of the N recovered in the leachates was in the nitrate form.
Luther C. Carson, Monica Ozores-Hampton, Kelly T. Morgan, and Jerry B. Sartain
adopted by the Florida Department of Agriculture and Consumer Services ( Bartnick et al., 2005 ). One BMP can be the use of CRFs, which are SFs encapsulated in a polymer, resin, or a hybrid of sulfur-coated urea occluded in a polymer coating ( Bartnick et
`Newtown' apples (Malus domestics Borkh.) treated weekly with urea at 10 g·liter-l or Ca(NO3)2 at 7.5 g·liter-1 for 5 consecutive weeks from late August were greener at harvest and during storage than comparable control fruit. A postharvest dip in Nutri-Save, a polymeric coating, was better for retention of skin greenness than a dip in diphenylamine and both gave greener apples than control (nondipped) fruit. Fruit treated with Ca(NO3)2 displayed lesions that were larger and more numerous than typical bitter pit in the control fruit.
M.D. Richardson and K.W. Hignight
Seed coating has been effectively used in the agricultural and horticultural industries for over 100 years. Recently, several turfgrass seed companies have been applying seed coating technologies to commercial seed lines, but there have been limited studies that have demonstrated a positive benefit of seed coating to turfgrass seed. The objective of this study was to determine the effects of two commercially available seed coating technologies, including a fungicide/biostimulant coating and a starch-based polymer coating, on tall fescue (Festuca arundinaceae) and kentucky bluegrass (Poa pratensis) in three soil types. Coated seeds were obtained from a retail outlet. Non-coated seed samples were developed by removing the coating from the seed just before planting. Neither coating technology had an effect on tall fescue speed of germination or total germination percentage in any of the soil types. Seed coating did have a positive effect on the speed of germination of kentucky bluegrass in a sandy loam soil, but did not improve the speed of germination or percentage emergence in the other soil types. These results support earlier findings that seed coating has minimal effects on establishment of turfgrass species. However, these coatings may provide benefits when attempting to establish turfgrasses in less than ideal conditions.
Bernd Leinauer, Matteo Serena, and Devesh Singh
A field experiment was conducted at New Mexico State University to investigate the effect of seeding rates and ZEBA polymer [starch-g-poly (2-propenamide-co-propenoic acid) potassium salt] seed coating on the germination and establishment of warm- and cool-season grasses, and cool-season blends and mixtures. Grasses were established at recommended and reduced (50% of recommended) seeding rates with coated and uncoated seeds under two irrigation regimes (98% and 56% reference evapotranspiration). With the exception of ‘Bengal’ creeping bentgrass (Agrostis stolonifera), the polymer coating did not improve germination of the turfgrasses tested 22 days after seeding (DAS). However, at the end of the establishment period (92 DAS), plots established with ‘Bengal’, Dunes Mix [mixture of ‘Hardtop’ hard fescue (Festuca longifolia), ‘Baron’ kentucky bluegrass (Poa pratensis), ‘Barok’ sheep fescue (Festuca ovina)], ‘Panama’ bermudagrass (Cynodon dactylon), and Turf Sense™ [mixture of ‘Baronie’ kentucky bluegrass, ‘Barlennium’ perennial ryegrass (Lolium perenne), and ‘Barcampsia’ tufted hairgrass (Deschampsia cespitosa)] achieved greater coverage (based on visual estimations) when coated seed was used compared with uncoated seed. Establishment was greater for ‘Bengal’, Dunes Mix, ‘Panama’, Turf Sense™, and Turf Saver™ [blend of ‘Barlexas II’, ‘Barrington’, and ‘Labarinth’ tall fescue (Festuca arundinacea)] when normal seeding rates were applied compared with reduced seeding rates. ‘Barleria’ crested hairgrass (Koeleria macrantha) plots did not establish, regardless of the treatments applied. Results showed that seed coating has the potential to improve establishment at recommended and reduced seeding rates and can compensate for less favorable conditions such as reduced irrigation, reduced seeding rate, or for a combination of both. At the end of the establishment period, not all grasses achieved coverage greater than 50%. Further research over a longer establishment period is needed to determine if coated seed can be beneficial in achieving full coverage.
Melissa L. Wilson, Carl J. Rosen, and John F. Moncrief
growing season in the first experiment. The first is a modified technique ( Savant et al., 1982 ) using the change in prill weights over time. First, the weight of the polymer coating in 3 g of PCU was determined using the following equation: where F C is
recommended and reduced seeding rates with coated and uncoated seeds under two irrigation regimes. Leinauer et al. (p. 179) observed that polymer coating on seeds improved germination of only one (creeping bentgrass) of the turfgrasses tested. However, the
Mark Gaskell and Tim Hartz
-release fertilizers (CRF) have been used in horticultural production for decades. Although a number of coating technologies have been developed, polymer coating dominates the market today; the chemical composition and coating thickness control nutrient release. A wide