Copyright © 2014 IJAIR, All right reserved 931 International Journal of Agriculture Innovations and Research Volume 3, Issue 3, ISSN (Online) 2319-1473 Field Evaluation of a Newly Introduced Thiamethoxam Insecticide and Neem Seed Water Extract Against the Predator Hippodamia Variegata in Sudan Ensaf S.I. Mohamed Shambat Research Station, Agricultural Research Corporation, Wad-Medani, Sudan Hayder Abdelgader Crop Protection Research Center, Agricultural Research Corporation, Wad-Medani, Sudan Abdalla Abdelrahim Satti National Centre for Research, Khartoum, Sudan email: satisattisat@yahoo.com Abstract — Naturally occurring biological control agents play an important role in suppressing many important agricultural insect pests under normal conditions. Regrettably, many synthetic pesticides are reported to impose negative impacts on beneficial insects. Therefore, considerable efforts are devoted in recent years to choose selective insecticides for combating noxious pests. Accordingly, field experiments were conducted on potato crop during two consecutive winter (December-March) seasons at Shambat Research Station, Khartoum North, Sudan, to study the side effects of a newly introduced insecticide Actara (thiamethoxam) 25 WG, applied at different rates, and neem seed kernel water extract (NSKWE) at two rates, on larvae of the coccinellid predator, Hippodamia variegata. The results indicated that Actara was toxic (IOBC class 4) to the larvae of H. variegata under the two experiments, while NSKWE was found to be safe to the predator. Such neem extract at its two rates (2.5% and 5%w/v) showed significantly the highest numbers of the predator in the two experiments. It is concluded that the tested neem treatments can be used safely against potato pests without adverse effect on the predatory larvae of H. variegata, but Actara should be avoided when natural enemies are active. Key Words — Predatory larvae, Hippodamia, neem, Actara, Side effect, toxicity, selective insecticide. I. INTRODUCTION Natural enemies (predators, parasites and entomopathogens) of insects play an important role in regulating agricultural pests under normal conditions. Therefore, exploitation of these enemies in biological control through various ways (importation, augmentation or conservation) comprises an important component of many integrated pest management programmes at the global level. Nevertheless, the extensive usage of several broad spectrum synthetic insecticides in field and vegetable crops is found to affect the natural enemies negatively [1]-[2]-[3]. The beneficial arthropods (predators and parasitoids) can be exposed to insecticides either directly through sprays or indirectly when get in contact with residues on plant surfaces, or by ingesting insecticide contaminated preys on host. To avoid such problems, harmful synthetic insecticides should be applied selectively (i.e., in terms of place, time and application technique), or otherwise selective chemicals with high or moderate safety to natural enemies may be selected and used. Thiamethoxam is a second–generation neonicotinoid compound with systemic and contact activity on economic important sucking pests (e.g., aphids and whitefly) of vegetables and other crops [4]. In Sudan, thiamethoxam (viz., Actara 25 WG) was recently recommended for the control of whitefly Bemisia tabaci on tomato and Aphis gossypii on potato [5]. On the other hand, biologically active substances from neem tree, Azadirchtca indica (A. Juss), have been evaluated against agricultural pests and their natural enemies in different parts of the world [6]- [7]-[8]-[9]. Likewise, neem seed water extract was recommended for the control of various pests on different vegetable crops in Sudan [10]-[11]-[12]-[13]. No adverse effects on populations of insect predators were recorded from the application of such neem extract on vegetables [11]-[12]-[14]. However, the important predatory groups recorded on vegetables in Khartoum and other parts of the country included: Coccinellids (e.g., Hippodamia variegata, Scymnus spp., Cheilomenes propinqua vicina and Coccinella undecimpunctata), chrysopids (e.g., Chrysoperla carnea), syrphids (e.g., Xanthogramma aegyptium) and different spiders [9]-[15]-[16]-[17]-[18]- [19]. Among the coccinellids recorded, H. variegata is the most abundant and most widespread in different parts of the country [12]-[16]-[19]-[20]. This rich fauna need to be thoroughly investigated and conserved to enhance their biological role in pest control. Objective: The side effects of Actara 25 WG (thiamethoxam) insecticide and neem seed kernel water extract, used for controlling potato insect pests, were evaluated in this study against the larvae of the coccinellid lady bird beetle, Hippodamia variegata, on the same crop (potato). II. MATERIALS AND METHODS Two consecutive field experiments were conducted on potato crop at Shambat, Khartoum North, Sudan, during winter seasons of 2002/03 and 2003/04. It was aimed to evaluate the side effects of Actara (thiamethoxam) 25 WG insecticide at 18.8, 25.0, 31.3 and 37.5g a.i./feddan (=42ha) and neem seed kernel water extract (NSKWE) at 2.5%w/v (25g neem kernel powder/L. water) and 5% (50g/L.) on larval population of the coccinellid predator, Hippodamia variegata. Moreover, Actara at 25g a.i/fed. mixed with NSKWE 25g /L. of water were tested in the second season.