Bassam Aoudi
General Commission for Scientific Agricultural Research-
Homs Research Center
Al-Ba’ath University, Faculty of Agriculture
2009
Abstract
Ecological studies were carried out on pear psylla Cacopsylla pyri L. (Psyllidae: Hemiptera) at Mokhtaria Research Station during 2007 and 2008 seasons. It was found that the actual activity pear psylla of winter form began on all pear cultivars in the 2nd week of February, and the first generation of summer form appear in the 1st week of April 2007 and in the 4th week of March 2008, and six peaks formed during 2007 and 2008 seasons.
The oviposition period of winter form was laid on the buds (venereal, green) in the 3rd week of February 2007 and extended until the 1st week of November, and in the 1st week of March to the 4th week of November 2008. The nymphs were obtained in the 2nd week of March and continued until the 1st week November in two seasons, and six peaks were formed.
The Results obtained revealed the presence of six overlapping field generations during 2007 and 2008 seasons. The effect of weather factors on the changes in the population density of pear psylla, the relationship between the changes in the number of (eggs, nymphs and adults) and the corresponding weather factors i.e. (max, min, R.H%, wind speed and sunshine duration) the correlation was positive and highly significant for maximum, minimum temperatures and sunshine duration, while for the mean RH% and rainfall was negative and highly significant, furthermore, insignificant effect was for wind speed during two years.
The highest number of adult pear psylla, C. pyri was recorded by the yellow colored sticky traps ratio from 59.97 to 82.97 insects/trap in two seasons 2007 and 2008, followed by the green colored sticky traps ratio from 53.03 to 74.03 insects/trap respectively and the lowest number of adult pear psylla was trapped by accident in (white, blue and red) colored sticky traps. The number of pear psylla stages was estimated for six pear cultivars during two years, the highest number of insect stages were attracting to Abo-Satl cultivar followed Beurre Giffard, while Red-Bartlette cultivar was the least infestation, but the cultivars (Spadona !Coscia and white- Bartlette) was the midst infestation.
Surveyed natural enemies were included in 10 species related to 6 families and 6 orders (8 species of predators) and (2 species of parasites). The predators of Anthocoris nemoralis (Fabricius), Chrysoperla carnea (Stephens), Coccinella septempunctata (L.), Adalia bipunctata L., Oenopia conglobata (L.), Exochomus quadripustulatus (L.), Eupeodes corollae (F.), Forficula auricularia L. Trechnites psyllae (Ruschka) and Psyllaephagus euphyllurae (Masi) were recorded during the two seasons.
The correlation in 2007 was positive and highly significant between insect stages (nymphs and adults) and predators (A. nemoralis, C. carnea, C. septempunctata) and eggs A. nemoralis and adults A. bipunctata and nymphs (O. conglobata, T. psyllae) and the correlation was insignificant for nymphs A. bipunctata and adults O. conglobata and eggs, nymphs E. corollae, while the correlation in 2008 was positive and highly significant between insect stages and A. nemoralis and nymphs (C. carnea, C. septempunctatam, O. conglobata, T. psyllae) and the correlation was insignificant for adults (C. carnea, C. septempunctata, O. conglobata) and eggs, nymphs E. corollae.
The efficiency of some plant extracts (Melia azedarach L., Schinus molle L. and Capsicum frutescens L.) was tested with group biocides (Beauveria bassiana Bals. And Bacillus thuringiensis Berliner) and chemical insecticides (white oil + Alpha cypermethrin, Abamectin, diflubenzuron) used to control Cacopsylla pyri L.
The results showed that efficiency of plant extracts were high in control pear psylla stages (egg, nymphs and adult) and mortality percentage after three days from spraying was 100, 99 and 77% for M. azedarach and 92, 86 and 67% for S. molle and 85, 76 and 72% for C.frutescens respectively, while mortality percentage from biocides was (87, 70 and 58%) and 84, 73 and 67% respectively. But mortality percentage from chemical insecticides (white oil + Alpha cypermethrin, Abamectin and diflubenzuron) was 100, 99 and 88% and 75, 96 and 85% and 70, 86 and 72% respectively.
Key words: Pear psylla, Cacopsylla pyri L., Ecological studies, weather factors, pear cultivars, natural enemies, control.