Treatments were applied in Italy, United Kingdom, and Spain to test their effectiveness in controlling superficial scald in apples (Malus domestica Borkh.) after cold storage. In Italy where mature `Red Chief' and `Golden Delicious' were stored at 3-4C for 4 months, scald incidence was reduced by postharvest dipping in a sucrose-ester based coating, Semperfresh, formulated with the antioxidants, ascorbyl palmitate, and n-propyl gallate. In the United Kingdom and Spain, early harvested `Granny Smith' were stored at 0C for 4 and 6 months. In the United Kingdom, ascorbyl palmitate applied with Semperfresh significantly reduced scald upon withdrawal from 4 months of storage near 0C, but not after 10 days at room temperature. Bringing the apples to ambient temperature for 20 hours 1 month into cold storage reduced scald almost as much as diphenylamine application, but the beneficial effects seen after 4 months of cold storage did not persist after 6 months of storage. In Spain, controlled atmosphere storage (3% O2 + 3% CO2) was as effective as diphenylamine treatment, even after 6 months of storage; CaCl2 was slightly effective after 4 months of storage, but none of the coating treatments significantly reduced scald. Treatments applied after 6 weeks were ineffective.
A.D. Bauchot, P. John, Y. Soria, and I. Recasens
J.C. Goffreda, J.C. Steffens, and M.A. Mutschler
Behavioral studies have shown that aphid resistance in Lycopersicon pennellii (Corr.) D'Arcy is due to the presence of sugar esters in glandular exudate of the type IV trichomes. In this study, various methods for the estimation of epicuticular sugar ester concentrations were examined. There was a significant negative relationship between the concentration of sugar esters on the leaf and the level of potato aphid infestation in a segregating L. esculentum × L. pannellii F2 population. Selection for sugar ester accumulation should be an efficient selection technique for the aphid resistance of L. pennellii and other species that synthesize epicuticular sugar esters.
Esmaeil Fallahi, S. Krishna Mohan, and Brenda R. Simons
Effects of several growth regulators and mineral nutrient sprays on `Rome Beauty' apple (Malus domestica Borkh.) russetting under climatic conditions of southwest Idaho were studied in the 1990 and 1991 growing seasons. Zinc (Zn-50), Calcium as a 12% liquid nutrient (Stopit-6), and fungicide (Polyram) sprays slightly increased, while GA (Provide) decreased fruit russetting.
In 1991, GA and repeated Semperfresh (sucrose ester, carboxymethyl cellulose and mono and diglycerides) applications reduced russetting while Bayleton application increased russetting. Russetting varied from year to year. In 1991, a season of severe fruit russetting, trees which received a fungicide treatment for powdery mildew had generally higher incidence of fruit russetting regardless of treatments. It is believed that interaction between relative humidity, temperature, and systemic sprays used for powdery mildew control contribute to `Rome Beauty' russetting.
M. Joseph Ahrens
Fresh, peeled, whole baby carrots are fast becoming the driving force in sales of fresh carrots. In 1991, 200 million tons were marketed to food service and retail outlets. “Peeled whole baby carrots” are mature carrots cut to 5 cm lengths and peeled in a modified potato peeler. Two problems have developed which are limiting the expansion of this market: 1) the product as currently packed develops a slimey rot in 10 days and 2) a “white blush” forms on the exposed surface of the product after 5 days.
Tests on the atmosphere of the bag indicated that the product was generating a low O2 environment, causing the growth of anaerobic rots. Evaluations of several film materials were undertaken to find a formulation which would provide an O2 level above 5% and CO2 below 7%, a level above which some cultivars are injured. Sucrose ester and cellulose based edible films and anti-oxidants were applied to the product to help eliminate white blush, which could be the product of dehydration or lignin formation.
A cellulose-base edible film supplied from the USDA and a mineral impregnated single ply low density polyethylene 1.5 mil bag were selected as the optimum packaging combination. Storage at 5C was improved to 50 days, with white blush and decay greatly reduced. Studies on the logistics of the edible film application are continuing.
H.F. Harrison, J. K. Peterson, and M. Snook
These studies were initiated to investigate severe growth inhibition observed when some vegetable crops were infested with corn spurry (Spergula arvensis L.). Interference by a natural population of the weed reduced the shoot weights of English pea (Pisum sativum L.) and collard (Brassica oleracea L.) by 93% and 72%, respectively. In a greenhouse experiment where light competition by corn spurry was prevented, broccoli (Brassica oleracea L.) shoot weights were reduced by corn spurry, but pea weights were not different from the controls. Homogenized corn spurry shoot tissue incorporated into a greenhouse potting medium inhibited the growth of both species, and a concentration effect was observed. Sequential hexane, dichloromethane, methanol, and 50% aqueous methanol extracts of corn spurry root and shoot tissue were tested for inhibitory activity using millet seed germination and broccoli seedling growth bioassays. Dichloromethane, methanol, and aqueous methanol shoot extracts were inhibitory to broccoli; whereas all shoot extracts inhibited millet germination. Shoot extracts were more inhibitory than root extracts. Further fractionation of the inhibitors using a combination of reversed-phase sephadex LH-20 and silicic acid column chromatographic procedures showed that a major portion of the millet germination inhibition was due to sucrose esters (SE). Preliminary characterization of the esters showed that there were four different SE groups. The major groups contained either octanoic or dodecanoic acid along with butanoic and petanoic acids. All groups inhibited seed germination at concentrations as low as 20 ppm. This is the first report of the SE class of defense chemicals in plant species outside of the solanaceae family.
Raymond A. Cloyd and Joshua D. Gillespie
.R. Bentz, J.A. 1994 Novel sucrose esters from Nicotiana gossei : Effective biorationals against selected horticultural insect pests J. Econ. Entomol. 87 1600 1607 Parrella, M.P. 1995 IPM: Approaches and prospects, p. 357–363. In: B.L. Parker, M. Skinner
Anna Marín, Anne Plotto, Lorena Atarés, and Amparo Chiralt
. 79 60 69 McGuire, R.G. Dimitroglou, D.A. 1999 Evaluation of shellac and sucrose ester fruit coating formulations that support biological control of post-harvest grapefruit decay Biocontrol Sci. Technol. 9 53 65 Nicolosi, E. Ferlito, F. Amenta, M
Carolina Contreras, Mauricio González-Agüero, and Bruno G. Defilippi
atmosphere (MA), have found that changes in gas concentrations improve pepino fruit storability and quality as in the case of other fruits ( Kader, 2002 ). Huyskens-Keil et al. (2001) studied the performance of edible coating (sucrose ester) and film