Search

The efficacy of XenTari® containing Bacillus thuringiensis var. aizawai (Bta), NeemAzal -T/S® (Azadirachtin A) and their combination were tested against the second and fourth larval instars of the old world bollworm (OWB), Helicoverpa armigera (Hübner). The Bta was applied in three concentrations of 0.5, 1, and 1.5 kg/ha while NeemAzal concentrations were 1, 2, and 3L/ha. The results showed a significant difference in the mortality percentage between the different concentrations. The Bta was more effective in the fourth larval instars. Seven days, after treatment, the mortality percentage in both second and fourth instar larvae reached 97% at concentration of 1 ml/l water. At the concentration of 2.7 g/l water, the mortality percentage caused by Bta in both second and fourth instar larvae increased gradually until the sixth day, where it reached 90% and 93%, respectively. On the other hand, the efficacy of NeemAzal-T/S® on the second and fourth instar larvae reached 97% seven days after treatment when applied at concentration of 1 ml/l water. The combination of XenTari® and NeemAzal-T/S® resulted in 100% mortality in the second instar larvae compared with respective mortality of 70% and 83%, when either of the two biopesticides was applied alone.

In addition to the arthropod pests, the date palm Phoenix dactylifera L is attacked by numerous non-arthropod pests, which include birds, rodents, bats, nematodes and snails. This review lists 57 species of birds reported in the agro-ecosystem of date palm. Of these, three species are major pests, 35 species are minor pests, 15 species are neutral and four species are birds of prey (raptors). The major bird pest species are the bulbuls, Pycnonotus spp., the rose-ringed parakeet Psittacula krameri and the house sparrow Passer domesticus . Rodents comprise 13 species, of which 12 are rats and mice and one species of porcupine. The major rodents are the roof rat Rattus rattus , the Norway rat Rattus norvegicus , the house mouse Mus musculus , the Nile rat Arvicanthis niloticus and the mole rat Nesokia indica . The Egyptian fruit bat, Rousettus aegyptiacus , is reported to be an important pest of date palm fruits. The review also lists 24 species of nematodes belonging to the following genera: Meloidogyne , Pratylenchus , Helicotylenchus and Tylenchorhynchus . Additionally, four species of land snails associated with date palm are listed. The article gives comprehensive information on the major non-arthropod pests of date palm regarding their distribution, biology, behaviour, nature of damage and possible management measures. Non-arthropod pests of minor importance are mentioned as checklists.

The main objective of this investigation was to assess the toxicity and growth regulating potential of Jatropha (Jatropha curcas L.), neem (Azadirachta indica A. Juss) and argel plant, (Solenostemma argel Hayne) against the desert locust, Schistocerca gregaria. The effect on fecundity, feeding behavior and egg hatchability was also studied. Argel of 5% concentration induced a significantly less (56%) antifeedant effect on desert locust nymphs compared with 79.62 and 78.92% for neem and Jatropha oils respectively. Significant mortality of 40.54 and 43.39% was recorded, 7 days after treatment, in insects treated with 10% concentration of neem and Jatropha oils respectively compared to 15.19% in the control. Argel resulted in the lowest mortality of 20.70% which was not significantly different from the control. There was a significant difference between treatments for the time it took surviving nymphs to moult to the next instar. Nymphs in the control group took significantly less time (11.3 days) to develop from the 5 instar to the 6 instar than those treated with neem and Jatropha oils where they took 17.5 and 16.5 days respectively. Argel was not Original Research Article American Journal of Experimental Agriculture, 4(8): 959-970, 2014 960 significantly different from the control. Jatropha oil significantly reduced the fecundity of females developed from nymphs treated in the 3 instar by 42.2% compared with 58.54% due to neem treatment. Argel caused no significant effect on fecundity of treated insects. Both Jatropha and neem oils resulted in 99.71% egg un-hatchability while argel had no significant effect. Of the three test products, only Jatropha and neem oil have shown growth regulating effect.

The date palm, Phoenix dactylifera L. (Arecales: Arecaceae) is subject to damage by numerous arthropod pests. This review lists 112 species of mite and insect pests associated with date palm distributed among 10 orders and 42 different families. Of these species, few are identified as major or potential pests of date palm tree. The listed species are classified according to their preferred part on the tree into: 34 species on the foliages, 30 species on palm bases, stem and roots, 26 species on inflorescences, bunch stalks, green and ripening fruits, and 22 species attacking date during harvest and storage. In addition to harmful insect and mite pests, more than 45 predators and parasitoids in 7 orders and 15 families are identified. Ten species are considered as major pests viz., the red palm weevil (Rhynchophorous ferrugineus), Old world date mite (Oligonychus afrasiaticus), lesser date moth (Batrachedra amydraula), Dubas date bug (Ommatissus binotatus), green pit scale (Palmapsis phoenicis), carob moth (Ectomyelois ceratoniae), longhorn date palm stem borer (Jebusaea hammerschmidti), rhinoceros beetle (Oryctes agamemnon), fruit stalk borer (Oryctes elegans) and almond moth (Cadra cautella).

This work was carried out to investigate the effects of grinding, storage conditions and duration on the bio-efficacy of neem seeds as a home-made insecticide against the red flour beetle Tribolium castaneum. Samples of neem seeds (intact and ground) were kept in small jute sacks and stored in the sun, refrigerator (4oC), and room temperature (28 ± 2oC) for two, four and six weeks in each condition. After the respective storage period, a water extract (5%) was prepared and sprayed topically on the 3 rd instar larvae of the beetle as well as on the pupal stage. A significant mortality of 62.83% resulted from the neem seeds stored in the refrigerator on the 7 th day of exposure. The seeds stored in the sun caused a mortality of 48.49%. The water extract from the seeds which were stored at room temperature, resulted in significantly high cumulative larval mortality of 50.30%. The efficacy of neem seeds kept in the sun was negatively affected and correlated with the length of storage period. However, the efficacy of the neem seeds stored in the refrigerator was increased with storage time. The pupal mortality due to spraying with water extract from neem seeds stored in the sun, refrigerator and room temperature was 49.67, 68.12 and 69.43% respectively. The mortality in the control (water treatment) was 7.33%. The results indicated that grinding of neem seeds before storage seems to have no effects on their efficacy.

Greenhouse experiments were conducted at Khartoum (Sudan) with the aphid predator Hippodamia variegata, two botanical and one synthetic insecticides: neem seed water extract (25 g fresh seed powder per l of water), NeemAzal T/S® (1 % azadirachtin A) and fenvalerate (Sumicidin® 20 % EC). An equivalent of 400 l/ha was applied with a plastic hand sprayer, containing 0.2 l Sumicidin (40 g/ha fenvalerate), 1.6 l NeemAzal (16 g/ha azadirachtin A) or 10 kg of neem seed powder (ca. 30 g/ha azadirachtin A was applied as neem seed water extract). The beetles were fed on Aphis gossypii reared on cucumber leaves. Four different stages of the predator were sprayed topically with the test preparations. In addition, beetles were fed on A. gossypii either topically sprayed or collected from cucumber plants, which soil was treated four days earlier. The preparations varied in their effects on the different stages of the predator. Neem weed water extract was less harmful to the predator than NeemAzal T/S. In topical treatments with NeemAzal T/S the corrected mortality (%) was: eggs 37.7, larvae 40.0, pupae 38.2, and adults 16.7; with neem seed water extract: eggs 15.1, larvae 26.7, pupae 29.4, and adults 10.0; with fenvalerate: eggs 86.8, larvae 100, pupae 73.5, and adults 100. Feeding L2 larvae and adults on contaminated aphids resulted in the following corrected mortalities (%): Sumicidin 100, NeemAzal ca. 40 and neem seed water extract 20/17 (larvae/adults). Feeding on aphids treated via the soil with neem seed water extract resulted at maximum in 26.4/16.7 % corrected mortality (larvae/adults), while no effects on the longevity of adults could be observed. So, in contrast to Sumicidin, neem preparations (being effective against pests) proved to be harmless for the beneficial beetle. The results are discussed concerning their importance for plant protection.

In greenhouse (Khartoum, Sudan), the effect of NeemAzal-T/S® (NA, at 20 g a. i. ha −1 ) on mortality of third instar nymphs of Jacobiasca lybica was not significantly different from that of Omethoate at 200 g a. i. ha −1 . Neem oil (at 0.2 g a. i. ha −1 ) was less effective. In two semi-field tests, numbers of J. lybica and potato yield were negatively correlated. The percentage yield losses were equal in both years. Two field experiments conducted in potato, using a VLV-technique with weekly treatments of 20 l ha −1 , showed similar mortality by NA and fenvalerate (20% EC at 140 g a. i. ha −1 ) in J. lybica and Bemisia tabaci . In Aphis gossypii , fenvalerate exerted a stronger effect (84%) than NA (77%). Potato yield was highest in NA and fenvalerate, lower in neem kernel water extract (NKWE; with 2–5 g a. i. ha −1 ), and equal to water treatment in neem oil (NO). In three similar field experiments in eggplant (aubergines), fenvalerate reduced J. lybica , B. tabaci and A. gossypii by 92%, 70% and 82%, respectively, followed by NA (86%, 61% and 78%). NO and NKWE were less effective. Eggplant yield was highest following NA-treatment, fenvalerate having a lower yield in one of the experiments. NO and NKWE increased the yield in only one of the three experiments. In eggplant, the frequency of stenophagous antagonists of the homopterous pests was affected negatively by fenvalerate, resulting in an unfavourable prey/predator ratio. The neem preparations induced only mild reduction of the antagonists, producing a favourable prey/predator ratio. Based on availability, the effects on pests, beneficials, and on yield, the use of NKWE may be recommended for plant protection in vegetables in the Sudan. Optimal concentrations, in excess of 2–5 g a. i. ha −1 , as used here, and new formulations remain to be studied.

Based on identification of collected pollen, in the area of North Khartoum, 21 plant genera (ca. 21 spp.) proved to be the main pollen sources for the honey bee Apis mellifera sudanensis. The imported dwarf honey bee Apis florea exploited 11 of these. The main pollen flow in the study area occurred between early December and late March. This is reflected by the amount of pollen collected by colonies of A. mellifera sudanensis. In spite of observations conducted soon after the introduction of A. florea, which gave hints of competition between the two bee species, further studies showed that A. mellifera sudanensis and A. florea do seem to coexist. This coexistence is based on different daily rhythms of pollen collection. A. mellifera collected pollen of Acacia seyal, date palm, and onions early in the morning (and partly in the late afternoon), while A. florea started pollen collection mostly later in the morning and ended it earlier in the afternoon. But in contrast to A. mellifera, A. florea was collecting pollen all day without interruption, even at very high air temperatures. Niche overlap (concerning the times of visits to flowers)between the two bee species was very low in date palms, and of medium importance in Acacia seyal. But it is remarkable that in total, A. florea is always present in higher numbers than A. mellifera sudanensis, on flowers. The significance of the introduction of A. florea to Sudan for pollination is discussed.

One-dimensional quasi-steady flow theories for flow through an orifice in a pipe are developed. These theories are presented in a form to be used with wave action calculations using the methods of characteristics. Steady flow experiments are described for determining the effective area of the orifice and the location of the plane of the pressure recovery. Non-steady flow tests using a single unit of a pulse generator are described. The results of non-steady flow experiments in the pipe are compared with the calculated pressure diagrams using a quasi-steady flow one-dimensional theory. These showed that the theory may be used for predicting the overall wave action in the pipe. In the plane of the enlargement, downstream of the orifice, the theory did not give an exact prediction of the pressure, particularly with small orifice area to pipe area ratios and high overall pressures. For small pressure changes, however, it is considered that the theory was satisfactory and may be used as the basis for calculating instantaneous mass flows if a square-edged orifice was used in pulsating flow streams.