Proc. of The International Conference of Environmental Sciences (ICES) Effect of alternative insecticides sprayed with two flow rates against some scale insects on mango trees by using conventional motor sprayer at Qalubyia governorate, Egypt. Nagwa A. Hassan1*, Sawsan G. Radwan1, Abd El Megeed E. Ammar2 and Omnia M.N. El-Sahn1 1 Department of Scale Insects and Mealybugs, Plant Protection Res. Inst., ARC 2 Department of Spray Technology Research, Plant Protection Res. Inst., ARC ABSTRACT Two field experiments were conducted on mango trees at El-Kanater El-Khairiya, Qalubyia Governorate. The first experiment is to survey the most assail insect pests started from January 2010 to December 2010 (one year). The results exhibit eight insect species belonging to three families; Diaspididae, Coccidae and Monophlebidae The white mango scale insect, Aulacaspis tubercularis and the soft scale insect, Kilifia acuminata appeared with high density (40.60% & 38.78%) of scale insect population, causing sever reduction in quantity and quality of mango crop followed by Insulaspis pallidula (6.05%) , Parlatoria pergandii (4.60%) .The second experiment was done at the 23rd December (2010) based on three principles: The first principle : to compare between two flow rates spraying; low flow rate (3.600L /min) and high flow rate (7.400 L / min) by using mineral oils (alboleum with rate of 2.5% as a winter oil) , (diver 1.5% as a summer oil) and admiral 0.005% (Which is analog of juvenile hormone) for controlling four previous pests on mango trees. The obtained data show that the modified spraying (3.600L/min) produced larger numbers of droplets than traditional method (7.400L/min) with all tested insecticides but traditional spraying produced higher volume mean diameter (VMD) of droplets . Admiral has superior number of droplets (891 droplets /cm2) and has the most percent of stability (82.6%) when it compared with the other two tested insecticides. The second principle : study the effecting of the spraying flow rates on tested insecticides. The results showed that, alboleum oil has same reduction efficiency when sprayed by two flow rates (86.16% and 87.46% reduction) while, diver oil appeared best action when sprayed by high flow rate (89.42%) reduction. In contrary, the best action of admiral appeared with low flow rate spraying (90.90%) reduction. The third principle: Study of the susceptibility of the four insect species to tested insecticides with both flow rates, the results refer to susceptibility of different stages of insects were varied according to the spraying volume e.g. A. tubercularis was receding and reduced when insecticides sprayed by modified spraying volume (3.600 L/min.) while K. acuminata , P. pergandii and I. pallidula have changeable susceptibility whereat the highest reduction in all stages of insects occurred when they treated by mineral oils with classical flow rate (7.400 L/min.) but admiral recorded its maximum reduction with the low flow rate volume. Keywords: scale insects, mango trees, spraying 21- 22 May (2013) - pp. 62 - 79 EFFECT OF ALTERNATIVE INSECTICIDES SPRAYED WITH TWO FLOW RATES ………. INTRODUCTION Mango trees, Mangifera indica L. (Anacardiaceae) are considered of the most popular fruit in Egypt. Egyptian mango occupied economic importance in the world market for rich flavor and tasty. The total cultivated areas in Egypt has been rapidly increased and reached about 222838 feddans in 2011, producing yearly about 598084 tons (Economic Affairs Sector, Ministry of Agriculture, Egypt). Mango trees are attacked by serious species of scale insects and mealybugs which belonging to the Superfamily Coccoidea (Family: Diaspididae, Coccidae and Monophlebidae). In general, these insects cause severe damage to mango trees by sucking out plant sap as food resource leading to shriveling of leaves and branches and impaired fruits; ultimately quality and quantity of yield are influenced. In addition a group of these insects like soft scale insects and mealybugs secreting excessive quantities of honeydew which accumulate on the upper surfaces of leaves encouraging the growth of the black sooty mould fungi (Steyn et al., 1993) causing a blocking to the respiration and photosynthesis processes. Also, the other group species of armored scale insects release phytotoxic substances while feeding (McClure, 1990). So, It was important to survey the most serious scale insects on mango trees. Among of these scale insects is the white mango scale insect, Aulacaspis tubercularis (Newstead) (Hemiptera : Diaspididae) which became recently a troublesome pest in all mango orchards in Egypt after it was restricted in Beni-Sweif and Minia Governorates (Radwan, 2003 and Abo-Shanab, 2012). The role of chemical control in reduction its abundance was discussed by some authors (Potenza et al., 1993; Labuschagne and Froneman, 1992; Villiers, 1992; Daneel and Steyn, 2004 and Lagadec et al., 2009). But, this insect have not wide controlling studied till now in Egypt, therefore, the present study is important to focus on this insect and the other three dominant insects (Kilifia acuminata, Insulaspis pallidula and Parlatoria pergandii) on mango trees and how to control them with a modern, economic and effective method. Using suitable sprayers or method of application is considered one of the most optimal chemical control programe for scale insects requires. Also, the sprayed spectrum of droplets could be considered as the vital factor affecting the biological and environmental results of application by means of pesticides. Osman (1983) found that droplet size plays an important role on the efficiency of the pest control programs. The main purpose of this work is to survey of scale insects and mealybugs infesting mango trees at El- Kanater El-Khairiya in Qalubiya Governorate, and to study the comparison between the efficiency of the two flow rates by using conventional motor sprayer; low flow rate (3.600 L/min.) and high flow rate (7.400 L/min.) by using some alternative insecticides in practical of controlling the most important insect pests. MATERIALS AND METHODS 1- Surveying of the scale insects and mealybugs: The study was carried out in mango orchard (about one fedddan) located at El-Kanater El-Khairiya, Qalubyia Governorate. Mango trees (variety Langra) were about 15 63 Hassan et al years old and not received any insecticides through the duration of the study. Monthly samples of 30 infested mango leaves were collected randomly for one year (from January 2010 to December 2010) and transferred directly to laboratory. Samples were examined carefully by the aid of stereomicroscope binocular to identify the scale insect and mealybugs and their population were recorded. 2- The efficiency of two flow rates by using conventional motor sprayer against some scale insects on mango trees: An experiment was conducted in December,23th 2010 at the previous location (EL- Kanater El-Khairiya) on the same mango trees to study the comparison between the efficiency of the two flow rates spraying by using the tested alternative insecticides for controlling the four prevalent insects infesting mango trees. Insecticides comprised: A- Mineral oils: 1- Alboleum oil: in a mayonnaise type formulated by Kafr El-Zayat Co. containing 80% mineral oil. The rate of application was 2.5 L. oil / 100 L. water. 2- Diver oil: A light mineral oil (miscible oil) produced by El-Helb pesticides and chemical Co. as emulsified concentrate formulation. It consists of 97% pure mineral oil + 3% emulsifiers to be emulsifible with water. The rate of application was 1.5 L./100L.water. B- Insect Growth regulator (IGR): -Pyriproxyfen (admiral 10% EC): It is formulated by Sµmitomo Chemical Co., Osaka, Japan, containing 10% a.i.2-(1-methyl-2-pyridyloxy) propylether-4-phenoxy phenyl. Rate of application was 50cm3/100 L. water. -Experimental design: Two tested flow rates were applied on mango trees which have similar age (15 years), size (height 5 X 7 m.) and infested with; Aulacaspis tubercularis (Newstead), Kilifia acuminata (Signoret), Insulaspis pallidula (Green) and Parlatoria pergandii Comstock. The mango trees were kept free away from any insecticidal contamination throughout one year before the experiment conduction. The selected area were divided into three identical plots (each plot contain 9 trees), the first plot was sprayed with the low flow rate 3.600 L./min, the second plot was sprayed with high flow rate 7.400 L./min. and the third plot was left as a control Twelve water sensitive papers (26X 76 mm) were obtained from Ciba Geigy, Switzerland, fixed on the upper, middle and lower levels of the tree in a diagonal line. At each level cards were mounted in north, south, east and west directions, respectively. Under each treated tree a wire holder of 30 cm high furnished with four water sensitive card were fixed inside ground surrounding each tested tree. The mean meteorological conditions during experiment were suitable for spraying operations. Tested treatments were distributed in randomized completely blocks design and each treatment were replicated 3 times. A spray gun was connected to the conventional motor pump by a 100 meter long hose the pump was capable to provide a pressure ranged between 20-30 Kg/cm2 64 EFFECT OF ALTERNATIVE INSECTICIDES SPRAYED WITH TWO FLOW RATES ………. The model of conventional motor sprayer was Genar and give effective swath width was washing spray , average working speed (1.2Km/h) - Examination of samples: 1- Measurements of the sprayed spots were carried out by a special scaled monocular strobin® lens (X15).according to Yates and Akesson (1963) and Trayford and Welch (1977) calculation of droplets were carried out on basis of that given by Gabir (2008) 2- Random samples of 30 infested leaves with scale insects were picked from each replicate (90 leaves/ treatment) immediately before spraying application and after two, four and six weeks from application. The samples were transferred to the laboratory for examination by the aid of stereomicroscope binocular.