Efficiency of certain biopesticides against the olive black scale insect , Saissetia oleae ( Olivier ) on olive trees at Giza Governorate , Egypt

An experiment was carried out to investigate the effect of some biopesticides for controlling the olive black scale insect, Saissetia oleae (Olivier) on olive trees at Giza Governorate, Egypt during April, 2010. Four biopesticides (Biover, Stanes-biocatch, Stanes-biomagic and Bioranza) and one plant extract (Nimbecidine) were tested. The obtained results showed that all tested biopesticides and one extract were able to decrease the infestation with the olive black scale insect on olive trees through the three post treatment counts. Data clearly showed no significant differences among their efficiency (over 85%) and Nembicidine gave 80%.


INTRODUCTION
Olive is one of the most economically horticultural crops in Egypt.The cultivated area of olive trees in Egypt has been rapidly expanded year after year.In 2000, it was 108322 feddans and it reached 163273 feddans in 2010.The quantity of production reached about 281745 tons in 2000 and 390932 tons in 2010.
Olive trees are infested with different scale insects among them the olive black scale insect, Saissetia oleae (Olivier).It causes weakness of trees and yield loss.As a result of intensive use of pesticides, there is a resistance of pests to conventional pesticides and decrease in the populations of natural enemies.It is important to search for alternative control methods such as bio-and microbial pesticides.
The aim of this investigation is to carry out the present experiment at Giza Governorate is to study the efficiency of some biopesticides against the olive black scale insect, Saissetia oleae (Olivier) infesting olive trees.

MATERIAL AND METHODS
The experimental orchard was applied by five treatments, 3 replicates for each treatment (15 trees/treatment), in addition to the untreated trees as control (15 trees).Spraying was applied on olive trees twenty years old, 2-2.5m height almost homogenous in infestation were not exposed to insecticides for two years prior to this experiment.The tested biopesticides were four bioinsecticides (entomopathogenic fungi) and one plant extract as follows:

Entomopathogenic fungus
Stanes biomagic: Containing 1x10 Motor sprayer "John Been" with a 600 liters tank, at a pressure of 400 P.S.I., at the rate of 20-25 liter per tree was used to secure complete coverage of all parts.
Samples of fifteen branches with their leaves were picked at random from all directions, replicated three times.These samples were taken in labeled paper bags to the laboratory for counting alive stages of the insect by the aid of stereoscopic microscope.
A pre-treatment count was carried out in April 2010 before spraying and 3 posttreatment counts were taken 3, 5 and 7 weeks after the application.The reduction percentages in the population density of S. oleae in relation to the pre-treatment count were calculated according to Henderson and Tilton formula, (1955) as follows: T a C b Reduction percentages = 1 -----------------x 100 T b C a Where: T b and T a are pre-and after-treatment counts, respectively.
C b and C a are untreated checks before and after treatment.Data of the percentages reduction were subjected to simple analysis of variance.

RESULTS AND DISCUSSION
Reduction percentages of the obtained data in the different stages of Saissetia oleae (Olivier) during April 2010 are presented in Fig. (1).These data showed the superior efficiency of the five tested biopesticides with three post treatments (3-7 weeks).Regarding the whole experiment (after 7 weeks), data indicated that the five tested compounds achieved satisfactory reduction in S. oleae population within the experimental period (7 weeks).The total population showed that Stanes-biocatch caused the highest reduction (91.68%),Nimbecidine (90.22%),Stanes-biomagic (88.74%),Biover (87.41) and Bioranza (82%) reduction, respectively.As a general trend, nymphs and adult females showed slightly more reduction in their populations than ovipositing (gravid) females.
Efficiency of certain biopesticides against the olive black scale insect, S. oleae (Olivier) 91 There were significant differences between the different periods where "F" value was 50.44 (at 5% level) and L.S.D. = 5.90.
The results of biopesticides are in agreement with those found by Valand and Vyas (1991) who found that the entomopathogens Aspergillus niger and A. flavus reduced the number of coccid Saissetia coffeae on Trichosanthes dioica in India.Also, Cozzi et al. (2002) in Italy who stated that the insecticidal activity of Fusarium larvarum against S. oleae was significantly reduced with time.The insecticidal activity of the formulations was evident even after 80 days.Kelany (2005) stated that neem formulations have more attention in controlling numerous pests in Egypt.El-Sobky (2006) recorded that jojoba oil showed 75.82% reduction against Aonidiella orientalis infesting Ficus nitida trees in Egypt.Sheng (2007) reported that Verticillium lecanii was highly pathogenic to S. oleae in Taiwan.Ezz et al. (2008) mentioned that Beauveria bassiana reduced the population of different stages of S. coffeae.Born et al. (2009) found that neem seeds extract gave the highest mortality of Diaspis echinocacti; while Metarhizium anisopliae was the least effective in Brazil.
The results of plant extracts are in agreement with those found by Kumar et al. (1989) who found that 1% kerosene and 4% neem-kerosene emulsion were considered effective against Coccus viridis.Chiu et al. (1993) found that oil emulsion of rubber tree seed oil with diesel oil (ratio 3:7) was very effective against Hemiberlesia pitysophila infesting pine trees in China.Chiu (1993) recorded that the control of H. pitysophila with chinaberry seed oil and rubber tree seed oil.Reddy et al. (1996) found that kemisal (garlic extract) at 1% effectively controlled Coccus viridis on Coffee under field conditions in, India.Ponte et al. (1998) recorded the efficiency of sprays with manipueira (a liquid extract from roots of cassava) with or without the addition of water against S. oleae in Brazil.Ismail et al. (2007) found that different extracts of the spicked centaury, Centaurium spicatum are effective against soft scale insect, Pulvinaria tenuivalvata on sugar cane leaves.Naik et al. (2009) mentioned that neem oil (5 ml/L) significantly reduced mussel scale, Lepidosaphes piperis.Eldoush et al. (2011) recorded that argel (Solenostemma argel Del.Hyne) and Usher (Calotropis procera Ait) should be recommended as an effective treatment to control the green date palm pit scale insect (Asterolicanium phoenicis Rao).