Nauclea diderrichii (De Wild and Th. Dür.) (common name Kusia and trade name, Opepe) is an evergreen tree found throughout the tropical rainforests of West Africa. It is heavily exploited for its timber and listed as vulnerable on the IUCN Red List of Threatened Species. The shoot borer Orygmophora mediofoveata Hamps, which attacks the nursery stage, has hampered attempts to establish N. diderrichii plantations in Ghana. This study examined the potential of four insecticides to protect N. diderrichii seedlings from O. mediofoveata attack and damage. Four insecticides–Pyrinex (chlorpyrifos), Dursban (chlorpyrifos), Cerox (dimethoate) and Golan (acetamiprid)–were applied to four-month-old N. diderrichii seedlings growing in full sunlight and under shade (80% of normal light), to evaluate their effects on incidence of attack, survival, severity of damage and growth. Insecticide treatment and light conditions had variable effects on the damage and growth of the seedlings after six months of evaluation. Seedling survival was not significantly influenced by the insecticide treatment. Percent survival of insecticide-treated seedlings did not differ significantly from that of control seedlings in full sun; however, under shade survival of treated seedlings was significantly higher than control seedlings. Nonetheless, control seedlings in full sun had higher survival (92.5%) than those under shade (62.5%). Insecticide-treated seedlings in full sun had lower incidence of shoot borer attack than those under shade. In full sun, dieback incidence following shoot borer attack was significantly lower for insecticide-treated than control seedlings. Growth in height and girth of seedlings was influenced positively by both insecticide and light, with girth especially being significantly lower under shade conditions. Currently, N. diderrichii seedlings are typically raised under shade; however, this study shows that raising seedlings in full sun with insecticide application could result in faster and better growth.

Weed management programs in ‘Superior’ potato with PRE and POST rimsulfuron treatments were investigated during 1992, 1993, and 1994 in Virginia on a State sandy loam soil. Common ragweed control by PRE combinations of metolachlor with linuron or metribuzin was higher when treatments included PRE or POST rimsulfuron. Common lambsquarters control was 93 to 96% by treatments that included POST rimsulfuron. In the absence of PRE herbicides, POST applications of 35 g ai/ha rimsulfuron plus 280 g ai/ha metribuzin controlled weeds comparable to sequential applications of this combination. Potato recovered from occasional terminal leaf chlorosis caused by rimsulfuron, rimsulfuron plus metribuzin, and organophosphate insecticides combined POST with rimsulfuron plus metribuzin. These studies demonstrate that rimsulfuron can be a useful component of weed management programs that include metolachlor, linuron, and metribuzin.

Field experiments were conducted to determine if aldicarb, disulfoton, or phorate applied in-furrow at 0.84 or 1.12 kg ai ha–1 affected cotton response to clomazone applied PPI or PRE at rates ranging from 0 to 1.12 kg ai ha–1. Disulfoton and phorate greatly reduced clomazone-induced chlorosis, stunting, and death of cotton seedlings. Compared with no insecticide or with dimethoate applied POST, aldicarb did not affect cotton response to clomazone. A clomazone rate by insecticide interaction was not observed for cotton yield. Clomazone reduced cotton yield at one of five locations. Insecticides affected yield at three locations, where highest yields were from cotton treated with aldicarb. In a separate experiment with 0.56, 1.12, and 2.24 kg ha–1 of phorate applied in-furrow and 1.12 kg ha–1 of clomazone applied PPI, phorate at all rates protected cotton from clomazone phytotoxicity.

Cotton tolerance of DPX-PE350 applied POST alone, mixed with acephate, carbaryl, or dimethoate applied at 220, 1100, or 280 g ai ha−1, respectively, or following aldicarb, disulfoton, or phorate applied in the seed furrow at 1.0, kg ai ha−1 was evaluated. DPX-PE350 at 170 g ae ha−1 did not adversely affect seed cotton yield, fiber length, fiber length uniformity, or micronaire but did decrease fiber strength. The insecticides did not alter cotton response to DPX-PE350. Entireleaf morningglory was controlled 92, 95, and 96% with DPX-PE350 applied POST at 56, 110, and 170 g ha−1, respectively. Mixing acephate, carbaryl, or dimethoate with DPX-PE350 did not affect control.

Field trials were conducted in 2005 and 2006 to evaluate application of glyphosate alone or plus the plant growth regulator mepiquat chloride with 20 different insecticides to second-generation glyphosate-resistant cotton at the pinhead square or first bloom growth stages. At 7 DAT, averaged across cotton growth stages and herbicide treatments, combination with insecticides profenofos and methomyl resulted in 5 and 9% plant injury, respectively, and were the only insecticide combinations that resulted in injury greater than glyphosate or glyphosate plus mepiquat chloride applied alone. By 14 DAT, cotton injury was less than 2% for all treatments. Averaged across cotton growth stages and insecticides, addition of mepiquat chloride to glyphosate resulted in a 4 and 6 cm height reduction at 7 and 28 DAT, respectively. Seed cotton yield and percent first harvest were similar for all treatments, indicating that cotton injury and height reductions observed after application did not result in yield reductions or maturity delays. Glyphosate combined with insecticides and mepiquat chloride, in accordance with herbicide labeling for second-generation glyphosate-resistant cotton, offers producers the ability to integrate pest and crop management strategies and reduce application costs with minimal effect on the crop.

A study was conducted in 2004 to determine the effect of coapplication of the insecticides acephate, acetamiprid, bifenthrin, cyfluthrin, cypermethrin, dicrotophos, dimethoate, emanectin benzoate, imidacloprid, indoxacarb, lambda-cyhalothrin, methoxyfenozide, spinosad, thiamethoxam, and zeta-cypermethrin; the plant growth-regulator mepiquat pentaborate; a foliar sodium calcium borate micronutrient solution; and a foliar nitrogen fertilizer solution with glyphosate on the efficacy of weeds that commonly infest cotton. Barnyardgrass, hemp sesbania, johnsongrass, pitted morningglory, and sicklepod were grown in outdoor containers and treated with glyphosate at 1,120 g ai/ha alone or in coapplication at the three-to four- or seven-to eight-leaf growth stage. Glyphosate efficacy, based on visual control ratings at 7, 14, and 28 d after treatment (DAT) and fresh weight reduction of weed biomass at 28 DAT, was unaffected by chemical coapplication or application timing. Averaged across application timing and visual rating interval, glyphosate alone controlled barnyardgrass 97%, hemp sesbania 68%, johnsongrass 98%, pitted morningglory 68%, and sicklepod 89%. These results indicate that glyphosate coapplications evaluated offer producers the ability to combine pest and crop management strategies and reduce application costs without sacrificing control of weeds evaluated.

Wetlands are one of the most altered natural systems due to the creation and development of agricultural landscapes. Some ofagriculture’s impacts are in relation to water quality decreases, due to the use of potentially toxic herbicides or pesticides, andthey are responsible of ecological alterations. This study shows the negative effect that two pesticides generate in a populationof the copepod Arctodiaptomus salinus in an aquatic ecosystem that is surrounded by intensive olive tree cultivation. Adultfemales and egg sacs of that calanoid copepod were exposed to different concentrations of copper sulphate and the pesticidedimethoate, to examine their tolerance response. The adult lethal concentration obtained was lower than the regular dose of pesticideused in olive agriculture. These results also reflect the negative effect over A. salinus secondary production as a consequenceof the increase in females and nauplii mortality and by the hatching rate reduction.

The corn earworm damage to seven maize cultivars TZB, TZPB, WYI, 096EP6, Farz 25, ‘Kewesoke’ and Local White, was assessed during the early and late cropping seasons of 1980 and 1981 at Ikenne and Ilora located in the rain-forest and derived savanna zones, respectively. The effectiveness of dimethoate and permethrin in controlling the earworms was evaluated. All the cultivars appeared susceptible to earworm infestation in the two ecological zones. Infestation was consistently and significantly higher in the early season and also in the rain-forest zone. It ranged from 71.5 to 86% in the early and from 28 to 36.8% in the late seasons, respectively, at Ikenne. At Ilora, infestation ranged from 53 to 82% and from 20 to 75% in the early and late seasons, respectively. Mussidia nigrivenella and Heliolhis armigera were the dominant species recorded damaging the grains.

Earworm infestation was significantly lower on plots treated wtih three applications of 0.05 and 0.1% a.i. permethrin at weekly intervals than on plots that received the same dosages and sprays of dimethoate and the control. Maize yields were significantly higher on permethrin-treated plots. The lower dosage of permethrin is recommended to reduce chemical residue on maize grains.

An evaluation of 17 chemicals was conducted in the field at Mwea-Tebere Agricultural Research Station to ascertain their efficacy against the red spider mites Tetranychus sp. attacking cotton in Eastern Kenya. The study became necessary owing to the inadequate control of red spider mites by the recommended acaricide, Dimethoate. Of the chemicals that performed well against the red spider mites, Kelthane, Akar, Morestan and Neoron were considered to be the most suitable replacements for Dimethoate because of their low levels of mammalian oral toxicity. Judged from the overall performance against the red spider mites, these acaricides were also about twice as effective as Dimethoate.

The studies show that the population of Maruca testulalis fluctuates greatly between the long and short rainy season and is significantly lower during the short and dry season, even when the cowpea crop is maintained under irrigation conditions. Studies on larval and pupal populations at Mbita Point, in Western Kenya and related farmers' plots showed lower populations under pure cowpea than under cowpea-maize intercrop, especially at 50% cowpea flowering stage (i.e. the second sampling stage). Although this difference was consistently manifested in the three seasons of experimentation there was no significant difference in larval population and extent of flower damage. Studies using three susceptible cowpea varieties (Ex-Lwanda, TVX 66-2H, and TVX 1193-059D) showed no significant difference in larval, pupal and adult populations when unsprayed. However, when sprayed with dimethoate (Rogor E 40) a systemic insecticide, significantly higher larval population was obtained in TVX 1193-059D, which shows the most vegetative growth of the three varieties. The borer damage on the flowers was not significantly different in all varieties under both the sprayed and unsprayed conditions. Studies using assessment of the different larval instars of M. testulalis in both sprayed and unsprayed conditions showed a continuous infestation of the crop throughout the season unless pod and flower production ceased. The fourth and fifth instar larvae were more abundant in pods than in flowers of the cowpea plant.