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It has been proposed by greenhouse producers that adding sugar to a stomach poison insecticide enhances the efficacy of the insecticide in controlling western flower thrips (Frankliniella occidentalis). As such, a series of laboratory, including no-choice and multiple-choice assays, and greenhouse experiments were conducted to determine if adding sugar-based compounds to insecticides enhances efficacy against western flower thrips. The sugar-based compounds evaluated were Mountain Dew, Diet Mountain Dew, white sugar, and brown sugar at two rates [initial (0.18 mL/100 mL and 0.12 g/100 mL) and high (0.36 mL/100 mL and 0.24 g/100 mL)]. A water control was also included in all the assays. In the laboratory experiments, western flower thrips adults and nymphs were not attracted to any of the sugar-based compounds with <60 s (out of 300 s total) spent in any of the treatments, and ≤29 s (out of 300 s total) spent in the treatments when the sugar-based compounds were mixed with three insecticides (tau-fluvalinate, pyridalyl, and spinosad). In the greenhouse experiments, the addition of the high rate of Mountain Dew (0.36 mL/100 mL) and brown sugar (0.24 g/100 mL) did not enhance the efficacy (based on percent mortality) of the insecticides against western flower thrips. There was no significant difference between the individual insecticide treatments and the mixtures with either Mountain Dew or brown sugar. This study is the first to quantitatively demonstrate that western flower thrips adults and nymphs are not attracted to sugar-based compounds and that it is not warranted to add these types of materials to spray solutions targeted for control of western flower thrips.
Radius of gyration (size), intrinsic viscosity, molecular weight, percentage of galacturonate, and percentage of neutral sugars were measured for chelate-soluble (CSP) and alkaline-soluble (ASP) pectins extracted from the cell walls of melting flesh (MF) and nonmelting flesh (NMF) peach [Prunus persica (L.) Batsch]. Weight percentage of cell walls, pectin content, and firmness were measured also. Peaches were extracted at 20, 21, and 22 weeks after flowering (WAF) and after various lengths of shelf storage at 25 ± 2C for the peaches picked at 21 WAF. Weight percentage of cell walls and firmness decreased markedly between the 21st and 22nd WAF; and between the 3rd and 6th day of storage for MF peaches as compared to NMF peaches. During these same periods, there were marked drops in the pectin content and the uronide content for MF as compared to NMF peaches. Size and intrinsic viscosity dropped markedly for CSP of MF peaches in comparison with NMF peaches during these same periods, whereas the molecular weight of CSP and ASP increased in MF peaches over that measured for NMF peaches. These results suggested that α -D-galacturonase (E.C. 3.2.1.15) was involved in softening only in the latter stages of ripening MF peaches. Further, cell wall polymers containing long thin pectin aggregates were destroyed, whereas cell wall polymers containing short thick pectin aggregates remained.
Abstract
‘Redlands Sweet Sue’ is a highly productive, nonpungent, smooth skinned pepper. The fruit shape is similar to ‘Sweet Banana’ and size and color is similar to ‘Cubanelle’. Plants were selected for resistance to the leaf spot bacterium Xanthomonas campestris pv. vesicatoria and one of three strains of potato virus Y (PVY) endemic in southeast Queensland. Plants continuously set fruit and offer wide adaptability in regions where the PVY complex is not a major problem.
Our objectives were to ascertain whether wheat (Triticum aestivum L. cv. SuperDwarf) plants, grown aboard the Russian space station Mir in the microgravity of space, exhibited any plant structure and histochemical changes compared with those ground-based plants grown in Moscow, Russia, and Logan, Utah. Plants were harvested at stages of ontogeny corresponding to day 6, 14, 25, 35, and 55 post-emergence and placed in 4% formaldehyde: 1% glutaraldehyde (4F: 1G) fixative, adjusted to pH 7.2, and stored in Aclam plastic bags. Upon return to earth, samples were dehydrated and embedded in Spurr's resin. Use of differential chromophores on semi-thin sections (1 μm) suggests no major artifacts in cellular structure. Enzyme localizations for lignin, carbohydrate, starch, alkaline and acid phosphatase indicate that plants grown aboard Mir appeared to have less lignin than ground control plants. (Supported by NASA Grant NCC 2-831 and the Utah Agr. Expt. Station.)