The commercial production and handling systems in Benue State was undertaken under a World Bank assisted project to identify and seek solution to constraints facing citrus farming in some rural parts of Nigeria. Selected areas noted for intensive fruit cultivation like Gbako,Yandev,Katsina-ala, and Aliade was covered in a survey by citrus agronomists and postharvest specialists. The study looked into processes and activities at farmers plots, agriculture department extension plots and nurseries, local markets and processing plants. Key production constraints identified include pest management and weed problems,bush burning, and high labor costs for farm operations. Lack of organized marketing outlets, high transport costs, and fruit decay at collection centers were the main bottlenecks facing the postharvest operations. Local processors face the problems of poor-quality raw material supply and the unstable price regimes every season. Investigation revealed that improved extension linkages that emphasize appropriate orchard management skills, integrated pest management, and careful handling should be introduced.
The concept of integrated pest management (IPM) has received widespread acceptance only within the past decade. Evidence of this is reflected in the increased number of articles dealing with pest management being published in scientific journals, and the increased number of papers presented at various scientific meetings. However, it is not all that new. A version of the IPM called supervised control was being practiced in alfalfa and cotton in California over 30 years ago and a sophisticated cotton insect scouting program was being used in Arkansas in the 1950s. Though these early programs were aimed at insect control, they demonstrated the advantages of extensive monitoring, which is the backbone of any pest management program.
Funding for this project was obtained through a grant from Northeast Integrated Pest Management Program. Appreciation is extended to Quintin Johnson for help in establishing and harvesting the plots and Tracy Wootten for her input and help
through the New York State Integrated Pest Management Program. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate
1 Assistant Professor. 2 Professor. 3 Technician. Research conducted at Cornell Univ., Dept. of Entomology Research Farm, Freeville, N.Y. This research was supported in part by a grant from the New York State Integrated Pest Management
partners; and the New York State Integrated Pest Management Program. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to
Field conditions associated with commercial cranberry (Vaccinium macrocarpon Ait.) production were simulated in greenhouse studies to determine the effect of soil surface characteristics on dichlobenil activity. Sand was compared with organic matter, in the form of leaf litter, as the surface layer. A seedling bioassay using alfalfa (Medicago sativa L.), a dichlobenil-sensitive plant, was employed to determine root growth response on herbicide-treated soil. When the herbicide was applied to a sand surface, root growth was greater as time after application elapsed, indicating loss of herbicide activity. Conversely, the presence of organic matter on the surface prolonged the activity of the herbicide. Composition of the surface layer was more important than the depth of the layer in determining herbicide persistence. The influence of cultural practices, such as the application of sand or the removal of surface debris, on herbicide activity should be considered when planning weed management strategies for cranberry production. Chemical name used: 2,6-dichlorobenzonitrile (dichlobenil).
`Titan' red raspberry (Rubis idaeus L.), highly susceptible to root rot caused by Phytophthora fragariae Hickman var. rubi Wilcox & Duncan (syns. P. erythroseptica Pethyb., “highly pathogenic” P. megasperma Drechs.), was planted in June 1990 in a silt loam naturally infested with the pathogen. Raked beds (0.36 m high) dramatically reduced disease incidence and severity relative to flatbed treatments. In contrast, metalaxyl at 372 mg·m-1 of row provided little benefit when applied to flat beds and provided consistently moderate but statistically insignificant effects when applied to raised beds. Relative to the flat bed system, primocane vigor was increased in 1992 by 16%, 190%, and 224% in the flat bed plus metalaxyl, raised bed, and raised bed plus metalaxyl treatments, respectively; total yields were increased by 7%, 231%, and 272% with these same respective treatment. The results indicate that raised-bed planting systems can provide substantial control of phytophthora root rot of red raspberries even when highly susceptible varieties are grown on otherwise marginal sites. Metalaxyl appears more effective as a supplement rather than substitute for raised beds under such conditions. Chemical name used: N- (2,6-dimethylphenyl) -N- (methoxyacetyl)alanine methyl ester (metalaxyl).
The hypothesis that carbon balance is the basis for differences in responses by lightly and normally cropped apple trees to European red mite (ERM) [Panonychus ulmi (Koch)] damage was tested. Mature `Starkrimson Delicious' (Malus domestica Borkh.)/M.26 apple trees were hand-thinned to light (125 fruit/tree, about 20 t/ha) or normal (300 fruit/tree, about 40 t/ha) target crop levels and infested with low [<100 cumulative mite-days (CMD)], medium (400 to 1000 CMD) or high (>1000 CMD) target levels of ERM. A range of crop loads and CMD was obtained. Mite population density, fruit growth, leaf and whole-canopy net CO2 exchange rates (NCER) were measured throughout the growing season of 1994. Leaf area and vegetative growth per tree were also measured. Yield and final mean fruit size were determined at harvest. Return bloom and fruiting were determined the following year. Total shoot length per tree was not affected by crop load or mite damage. ERM reduced leaf and whole-canopy NCER. Normally cropped trees showed fruit weight reduction earlier and more severely than lightly cropped trees with high mite injury. Variation in final fruit weight, return bloom and return fruiting was much better related to whole-canopy NCER per fruit than to CMD.
Field experiments were conducted to assess how sweetpotato [Ipomoea batatas (L.) Lam.] clones interfere with weeds and how clones tolerate weed interference. Eleven clones with architecturally different canopies were evaluated for yield, canopy surface area and dry mass, weed dry mass, and light interception at ground level. A 2-fold difference in ground area covered by canopy surface area was observed among the eleven clones 42 days after planting, and a 3-fold difference in canopy dry mass at harvest. Yields were reduced from 14% to 68% by weed interference. The yields of high-yielding clones, `Beauregard', `Excel', L87-125, `Regal', `Centennial', and W-274, were reduced to a significantly greater extent by weeds than were yields of the other five clones. No differences were observed between clones for weed suppression as measured by weed dry mass at harvest and ground light interception. Short-internode and long-internode clones had similar competitive abilities. Yield of high-yielding clones was impacted more by weed interference than was that of low-yielding clones.