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  • Author or Editor: John Damicone x
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Drip-irrigated, stake-and-weave supported tomato (Lycopersicon esculentum) plots were established in 2005 and 2006. All plots (except controls) were treated with a kaolin particle film product (Surround WP) mixed at 0.5 lb/gal of water and applied with a pressurized hand sprayer. Sprays began after transplanting and were repeated as needed to maintain a particle film on the foliage. Sprays were discontinued either at anthesis, at first green fruit 5 cm in diameter, or at first colored fruit harvest. Multiple hand harvests were made as fruit matured. In 2005, all kaolin treatments reduced marketable fruit number and weight, whereas in 2006 there were no significant effects. Cull fruit weight and average weight per marketable fruit were unaffected by treatments during either year. Results indicate that when applied before harvest begins, Surround may not improve marketable yields of fresh tomatoes.

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Weather-based disease advisories have allowed vegetable producers to optimize their fungicide applications. These models typically use only past weather data to identify times of potential disease outbreak. The Oklahoma Mesonet has developed a new Spinach White Rust Advisory that improves grower disease decision support by combining forecast, current, and past weather data in calculating infection periods. The decision-support component issues initial spray advisories, based on infection hour accumulation from the first true-leaf stage or from a previous fungicide application date for subsequent sprays. The advancement in this model in relation to traditional weather-based disease advisories are: incorporation of an 84-hour forecast, hourly model recalculation, cultural practice customization, user site selection from any of 110+ statewide sites, and immediate access to detailed historical data. The model is available on the Oklahoma Mesonet AgWeather website (http://agweather.mesonet.org).

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Benomyl was compared with copper hydroxide, azoxystrobin, tebuconazole, acibenzolar-S-methyl, and basic copper sulfate for efficacy of cercospora leaf spot [incited by Cercospora brassicicola P. Henn] management on turnip greens [Brassica rapa L. var. (DC.) Metzg. utilis]. Treatments included various application times and were evaluated in three field experiments over 2 years. The few yield effects that occurred were not consistent between years. Copper hydroxide and basic copper sulfate were not useful alternatives to benomyl due to a combination of phytotoxicity symptoms and ineffective disease control. Inconsistent results were observed with acibenzolar-S-methyl. A single, early application of tebuconazole greatly reduced cercospora leaf spot severity relative to the control in both years. Tebuconazole may be a good alternative to benomyl if a label can be obtained. Multiple (at least two) applications of azoxystrobin may be needed to achieve the same degree of cercospora leaf spot control as would result from a single properly timed application of benomyl. Although azoxystrobin is now labeled for turnip greens, grower costs will likely increase as a result of benomyl being discontinued. Chemical names used: methyl-1-[(butylamino)carbonyl]-H-benzimidazol-2-ylcarbamate (benomyl); methyl (E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate (azoxystrobin); alpha-[2-(4-chlorophenyl)ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (tebuconazole); 1,2,3-benzothiadiazole-7-thiocarboxylic acid-S-methyl-ester (acibenzolar-S-methyl).

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Nine nematicide treatments were evaluated from 1993 through 1995 in field experiments on paprika pepper (Capsicum annuum L.). Materials tested included a chitinurea soil amendment and six chemicals: fosthiazate, carbofuran, aldicarb, oxamyl, fenamiphos, and 1,3-dichloropropene (1,3-D). Stands at harvest were increased relative to the control by chitin-urea, fosthiazate, and 1,3-D, but only fosthiazate increased marketable fruit yield relative to the control. Aldicarb reduced preharvest nematode populations relative to the control, but aldicarb did not result in a significant fruit yield increase. Chitin-urea was the only treatment to produce a net increase in nematode counts from preplant to preharvest in all three years. Although fosthiazate was promising, nematicide treatments were of limited benefit under the conditions of these studies. Chemical names used: (RS)-S-sec-butyl O-ethyl 2-oxo-1,3-thiazolidin-3-ylphosphonothioate (fosthiazate); 2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate (carbofuran); 2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoyl)oxime (aldicarb); methyl N′N′ -dimethyl-N-[(methylcarbamoyl)oxy]-1-thiooxamimidate (oxamyl); ethyl 3-methyl-4-(methylthio)phenyl(1-methylethyl) phosphoramidate (fenamiphos).

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Nematodes (Meloidogyne sp.) are a potential problem when paprika peppers (Capsicum annuum L.) are grown in fields historically planted to peanuts (Arachis hypogaea L.). Nine nematicide treatments were evaluated over 3 years in field experiments on paprika pepper. Materials tested included the chitin nematicide ClandoSan and six chemicals: fosthiazate, carbofuran, aldicarb, oxamyl, fenamiphos, and dichloropropene. Stands at harvest were increased relative to the control by ClandoSan in 2 of 3 years. Other horticultural effects (plant dry mass and fruit yield) were minimal for all nine nematicide treatments. No one nematicide treatment consistently reduced nematode counts at harvest relative to the control. Nematode counts at harvest were greater in plots treated with ClandoSan than in plots treated with any other material in 2 of 3 years. Nematicide treatments were not cost effective under the conditions of these studies.

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Geographical dispersion of production hampers watermelon integrated pest management (IPM) information delivery in Oklahoma. Melon Pest Manager (MPM) was created to educate and provide advisory information on IPM. Available at www.lane-ag.org, the site emphasizes information relevant to the area. MPM was conceived as Internet availability grew and was recognized to have potential for enhancing IPM implementation. Survey of producers suggested the value of Web-based information may depend on how easily it can be accessed. MPM was designed to provide easy access to watermelon IPM information. Compared to printed literature, web-based format is easier to revise and suited to presentation of information that applies yearly as well as that which may change frequently. MPM provides general discussion of melon IPM tactics and pest-identification and time sensitive information such as pest advisories and pesticide registration changes. MPM offers opportunity for novel presentation of educational information such as the real-time posting of field demonstrations. An initial challenge was to balance site development, promotion and education. Promotion and education followed placement of watermelon IPM tactic information on MPM but preceded advisory and pest identification. Pest identification links to existing sources are enhanced by material prepared for MPM. Progress is slowed by the need for expert intervention and the availability of images and descriptive information. Education on use of advisory resources (e.g., disease forecasters) is a high priority. However, availability and applicability of such products is dependent on the home site. The original concept envisaged mapping of pest activity using grower, extension agent and expert input. Time demands of other components of the site delay development of this aspect. Pest alerts are posted and distributed to county extension offices.

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