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The predatory bug Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important biological control agent in Asia that is often released on field crops and in greenhouses to control pests on vegetable and ornamental plants. This study compared the developmental and reproductive performance of O. sauteri on monotypic diets of four aphid species, western flower thrips, and two-spotted spider mite. Thrips emerged as the optimal prey type, consistent with findings for many other Orius spp. A diet of Frankliniella occidentalis (Pergande) yielded the fastest development, largest adult body size, shortest pre-oviposition period, and highest fecundity and longevity. Tetranychus urticae (Koch) was the next most suitable prey by most performance measures. Among aphids, Myzus persicae (Sulzer) was the most suitable and Aphis gossypii Glover the least suitable, with Aphis craccivora Koch and Megoura japonica (Matsumura) intermediate. Female O. sauteri were larger than males and female body mass varied more with prey type than did that of males. Despite the variation in performance among prey, all prey species yielded equally good juvenile survival and none would be expected to negatively impact the numerical response of O. sauteri in biological control applications where these arthropods form part of the prey complex.

The nutritive quality of aphids, conspecific and heterospecific eggs as food for ladybirds is a controversial issue. If ladybirds find aphids more palatable than eggs then they are more likely to efficiently exploit and be biocontrol agents of aphids. If eggs of conspecific or heterospecific ladybirds are more palatable than aphids these biocontrol agents may either impede aphid pest suppression or become a threat to other species of ladybirds. Thus, prior to formulating predatory guilds of ladybirds the nutritive quality of their eggs compared to that of the target aphid needs to be determined. In this regards, the present study evaluates the nutritive quality of an ad libitum supply of: (i) pea aphid, Acyrthosiphon pisum (Harris), (ii) conspecific eggs and (iii) heterospecific eggs as food for Coccinella septempunctata (L.) and Coccinella transversalis Fabricius (Coleoptera: Coccinellidae), by determining the stage specific predation and developmental attributes of these two ladybirds reared on these diets. The conversion efficiencies and growth rates of young (first, second and third) larvae of both species of ladybirds were higher than those of fourth instar larvae and the consumption rates of fourth instar were higher than those of young larvae when fed on the three diets. When fed aphids the pre-imaginal development was faster, the consumption rates, conversion efficiencies and growth rates higher, adults bigger and mortality lower than when fed on conspecific eggs. The larvae of C. septempunctata consumed and completed their development when fed eggs of C. transversalis but the first instar larvae of C. transversalis did not consume the eggs of C. septempunctata and died of starvation. The dominance of C. septempunctata over C. transversalis in agricultural fields may be due to it consuming and utilizing aphids more efficiently and as a consequence growing faster and suffering a lower mortality along with its ability to consume and complete its development on eggs of C. transversalis. Thus, both these predators may not continue to coexist as predators of the pea aphid in agricultural fields since C. septempunctata may become a greater threat to C. transversalis in the future.

The influences of arbuscular mycorrhizal (AM) fungi (Glomus intraradices (G) and Acaulospora laevis (A)) with Trichoderma viride (T) and Pseudomonas fluorescens (P) alone and in combinations on growth, mycorrhization, chlorophyll content, nutrient uptakes, and yield of broccoli plants were studied in pot culture under glasshouse conditions. The obtained results demonstrated that the single inoculation of broccoli plants with T significantly increased the above-ground fresh weight, root length, chlorophyll b, head diameter, root phosphorus, and shoot nitrogen in comparison to uninoculated control plants. On the other hand, consortium of G+A+T+P significantly increased plant height, above-ground dry weight, root fresh weight, chlorophyll a, head fresh weight, and root nitrogen content. Similarly, G+T showed maximum leaf area and P alone showed maximum uptake of shoot phosphorus. When P was supplied along with T, early flowering was recorded. AM fungal colonisation was negligible and only root tips were found infected in G or A treated plants which confirms low dependency of broccoli on AM fungi.

The quality of untreated water used by dry season vegetable growers determines the safety of the vegetables produced for human consumption. Traditionally, small scale vegetable farmers site their farms along banks of streams which gradually dry up during the dry season resulting in isolated pockets of ponds at different intervals along the path of the streams which are used by farmers to irrigate. A field experiment was initiated at Ibadan to ascertain the quality of irrigation water used to produce vegetables along Ona-stream during the dry season. Five isolated ponds and one locally dug well were sampled and analysed to ascertain the heavy metals status. Results of soil analysis from five farms (A-E) sited very close to the stream revealed high concentrations of heavy metals ranging from 0.96 to 2.34 mg/kg for Pb, 0.72 to 2.16 mg/kg for Cr and 0.30 to 0.92 mg/kg for Co while farmland F sited about 90m away from the stream was free of Pb, Cr and Co contaminants. Locally dug well F water was free of Cr, Co and Pb while isolated ponds had Cr, Co and Pb in the range of 0.01 to 0.23 mg/kg which is beyond safe consumption thresholds. There were strong correlations between heavy metals in water and vegetable for Cr (0.992), Cd (0.599), Ni (0.614) and Pb (0.552) indicating that the hygienic status of dry season vegetables is largely determined by the quality of irrigation water. In addition, all vegetables irrigated with untreated isolated ponds contained Cd, Pb and Ni concentrations above maximum permissible standard which could pose risk to human health. Therefore, farmers should be enlightened on the need to use hygienic water for irrigation. Construction of shallow wells on the farms instead of using contaminated stream water directly could be a better option for healthy and sustainable agriculture.

As opposed to direct sowing, production of seedlings of vegetable crops for transplanting is commonly practiced by vegetable growers. This study was undertaken to determine the effects of humic acid on the growth and the macro- and micronutrients contents in tomato (Lycopersicon esculentum) and eggplant (Solanum melongena var. esculentum) seedlings under greenhouse conditions. Different levels of humic acid (50, 100, 150, 200 ml/l) were applied to growing media (peat) after transplanting of examined seedlings of the species every ten days by the time of planting. The highest growth rate for leaf stem and root growth were obtained at 50 and l00 ml/l HA and 50, 100, 150 ml/l HA for tomato and eggplant seedlings, respectively as compared to the control. The highest content of macro- and micronutrient contents were obtained at 100 ml/l HA and 200 ml/l HA for tomato and eggplant seedlings, respectively as compared to the control

This research was conducted to determine the effects of two biostimulants (humic acid and biozyme) or three different salt (NaCl) concentrations at the temperature 10, 15, 20 and 25 deg C on parsley, leek, celery, tomato, onion, lettuce, basil, radish and garden cress seed germination. Two applications of both biostimulants increased seed germination of parsley, celery and leek at all temperature treatments. Germination rate decreased depending on high salt concentrations. At different salt and temperature garden cress was characterized by the highest germination percentage to other vegetable species. Interactions between NaCl concentrations and temperatures, as well as biostimulants and temperatures were significant at p = 0.001 in for all vegetable species except onion in NaCl concentrations and temperatures that of the control

The study examined the determinants of the perceived effectiveness of an organic fertilizer used by farmers in Oyo state, Nigeria. A stratified and purposive sampling technique was used to select 110 respondents from three major vegetation zones of the study area. Descriptive statistics were used to present the findings of the study while the Chi-square analysis was used to test the study hypotheses. Data revealed that 77.3% were aware of the organic fertilizer while only 60.0% of those aware made use of the fertilizer. Among the users, 37.3% applied 25 g of the organic fertilizer per crop stand which was largely on maize (92.16%). Average rate of application was 0.40 tons per hectare. Application method was mainly through side dressing (58.82%) and dig and cover (29.41%). Time of application varied from the time of sowing to 4 weeks after planting with the majority of farmers (64.71%) applying at 2 weeks after planting. Interest in the continuous use of the fertilizer was high (62.75%) and the majority of users (52.95%) perceived that the organic fertilizer was effective. Chi-square analysis revealed that the rate and method of application were significantly related to the effectiveness of the fertilizer (square chi = 15.66, P less than 0.05 and square chi = 8.79, P less than 0.05, resp.). Rate and method of application are thus significant determinants to fertilizer effectiveness. Extension activity should therefore focus on farmer education to ensure proper use of the organic fertilizer for maximum productivity.

The hypothesis that generalist predators limit associated prey populations was tested using spiders, a group classically thought to be an insignificant component of the agroecosystem. Two habitat manipulations (addition of mulch and flowers) in separate and combined treatments were utilized to enhance spider numbers in a mixed vegetable system. Compared to control plots, significantly higher spider densities were observed in the plots to which mulch alone or both mulch and flowers had been added. Insect damage to the plants was significantly lower in the plots to which mulch had been added as well, which correlates with the lower numbers of pest insects in plots containing mulch. That spiders were the probable cause of the effect was demonstrated in plots containing both mulch and flowers but from which spiders had been systematically removed. Removing spiders from plots with mulch and flowers removed the effect of this treatment on pest numbers and plant damage. In addition, 84% of the predators observed foraging in the study areas during timed watches were spiders and 98% of the predation events observed were by spiders. In a separate experiment, spiders were added to a subset of individually bagged broccoli plants that had been infested previously with known numbers of herbivorous pests. Plant damage in bags lacking spiders averaged 93.3%, whereas damage averaged 31.8% in bags to which spiders had been added.

Net N-mineralization and nitrification from soil organic matter and from vegetable crop residues (leaf-blades of cauliflower and stems of red cabbage) were measured at 4 temperatures during aerobic incubation in the laboratory. C-mineralization from leaf-blades of cauliflower was monitored at 3 different temperatures. N-mineralization from soil organic matter was best described by zero order kinetics N(t)= kt whereas N- and C-mineralization from the crop residues were described by single first order kinetics. Stems of red cabbage mineralized much more slowly than leaf-blades of cauliflower. S-shaped functions were fitted to the relationship between the rate constants of both C and N-mineralization and temperature. The rate parameter κ of the S-shaped function reflects the temperature dependence of the mineralization rate κ. The parameter κ for N-mineralization of the stem material (κ=5.36) was significantly higher than for the leaf-blades (κ=3.38), indicating that there is a strong interaction between temperature and resistance to degradation in the soil. N-mineralization from soil organic matter was least sensitive to temperature (κ=2.63). Temperature dependence of nitrification was not significantly different from mineralization over the temperature range considered. Rate constants for C-mineralization of cauliflower leaf-blades were higher than for N-mineralization, but the temperature dependence of the rate constants was not significantly different for both processes.

Description of the subject. Despite the importance of tomato in Central Africa, little is known about the weed flora occurring in tomato crops in this part of the world. Objectives. We aimed to provide a comprehensive description of the weed flora found in tomato crops in the mountainous region of South Kivu, DR Congo. Method. Floristic inventories were made in four cultivation zones of the Kabare territory, South Kivu. Results. In total, 79 species (belonging to 64 genera and 31 families) were recorded. The most species-rich families were Asteraceae and Poaceae. Therophytes and geophytes were the dominant life forms. Weed diversity was not significantly different between sites but species composition varied considerably, likely in relation to soil type. Based on the frequency and the abundance, the most problematic weeds were Commelina benghalensis, Galinsoga quadriradiata, Commelina diffusa, Galinsoga parviflora, Bidens pilosa, Oxalis debilis and Digitaria velutina. Conclusions. The weed flora in tomato fields of the mountainous regions of DR Congo is diversified, but only a few cosmopolitan species are problematic. Flore adventice de la tomate dans le Sud-Kivu montagneux, RD Congo Description du sujet. En dépit de l’importance de la culture de tomates en Afrique centrale, peu d’études sur la flore adventice de cette culture y ont été réalisées. Objectifs. Cette étude visait à caractériser la flore adventice des cultures de tomates dans les régions montagneuses du Sud-Kivu, RD Congo. Méthode. Des inventaires floristiques ont été réalisés dans quatre zones de culture du territoire de Kabare, Sud-Kivu. Résultats. Au total, 79 espèces, réparties en 64 genres et 31 familles, ont été inventoriées. Les Asteraceae et les Poaceae constituent les familles les plus diversifiées. La flore est dominée par les thérophytes et les géophytes. La diversité spécifique était comparable entre les zones de culture, mais la composition en espèces y était variable. Sept espèces d’importance agronomique ont été identifiées : Commelina benghalensis, Galinsoga quadriradiata, Commelina diffusa, Galinsoga parviflora, Bidens pilosa, Oxalis debilis and Digitaria velutina. Conclusions. La flore adventice de la tomate dans les régions montagneuses du Sud-Kivu est diversifiée. Néanmoins, les quelques espèces problématiques sont des espèces cosmopolites.