The effect of temperature on the development of the predator Hippodamia variegata
(Coleoptera:Coccinellidae) reared on the green peach aphid Myzus persicae Sulzer
(Homoptera:Aphididae) was determined at five constant temperatures (15, 20, 25, 30
a
nd 35)°C under laboratory conditions. The present study was conducted at Latakia
Agricultural Research Center during 2015 and 2016. This study aimed to determine
the impact of temperature on the development of the predator H. variegata to
identify the suitable temperature for rearing this predator. The duration (days) and
survival (%) were measured for this predator. Results showed that temperature had
a significant effect on the development of H. variegata immature stages, whereas
the development time from larvae to adult decreased with increasing temperature
at thermal range (15-35)°C. The longest larval developmental duration was 24.84 days
at 15°C, and the shortest duration was 4 days at 35°C. Also, the shortest pupal
duration was one day at 35°C and the longest period was 9.84 days at 15°C. The
lowest developmental time from eggs hatching to emergence of adults was 6 days
at 35°C, while the longest developmental time was 36.84 days at 15°C. Also the
ratio of larval survival was affected by temperature, this ratio was (26%, 52%,
77%, 34%, 4%) at (15, 20, 25, 30 and 35)°C respectively. The results of statistical
analysis showed that there were significant differences between the five constant
temperatures in all studied biological characteristics, and the temperature 25°C was
suitable for a successful rearing of the predator H. variegata.
A study for tribe Coccinellini (Coccinellidae, Coeloptera) was conducted in
south of Syria. The objective of this study was to determine the species and
their relative abundance. Members of this tribe important for biological control
because they
are primariy predators on aphids. The adults Coccinellids were
collected from agriclture and natural ecosystems from August 2001 the end of
July 2003. The results revealed the presence of 10 species belonging to 8 genera.
The investigation included their abundance and distribution in south of Syria.
The species Anisosticta novemdecimpunctata (L.) was recorded in Syria for the
first time. The Adonis ladybird, Hippodamia (Adonia) variegata (Goeze), was
the commonest species. and the most abundant ones were H. variegata (Goeze)
44.9%, Oenopia conglobata (L.) 27.7% and Coccinella septempunctata L.
10.5%.
The life cycle of Cacopsylla bidens was studied in the souther region of Syria
(Sweida) during 1999-2000. This insect was first identified in Syria as asole-host
species, which enters the winter dormancy as an adult out of the pear orchards
in bot
h the sites. The insect enters the pear orchard at the end of the winter,
and the summer adult insects emerge after the fall of flowers petals, and
continue the whole.
Summer up to mid of autumn, and the winter form emerges during the first
10 days of August. The harsh environmental conditions and the biological
enemies (predators) push the insect to migrate out of the pear orchards during
autumn. A survey and identification of the insect natural enemies was carried
out during the whole study period, they were Anthocoris nemoralis, Orius
horvanthi, Campylomma spp., Deraecoris spp., and Psallus spp., which
registered on C. bidens at few locations, in Alkafer district on the trees of Pyrus
Syriaca during summer. The encyrtidae parasoitoid Trechnites psyllae was
registered for the first time in Syria on the nymphs of C. bidens as a dominant
parasite. The highest percentage of parasite (66%) was found at Saragaia
Researchs Station during the autumn generations. And also the parasite
Ennotus spp. was noticed, but with low density at the end of the season.
A survey of the natural enemies of woolly apple aphid Eriosoma lanigerum
(Hausm.) was conducted in unsprayed orchards in the mountain region of
Sweida, Syria. Twenty-six species were found, belonging to Coleoptera,
Dermaptera, Diptera, Heteroptera
, Neuroptera. Coccinella septempunctata L.
was the most abundant predator at the beginning of the season. The coccinellid
Oenopia conglobata (L.) occurred in less numbers and had a secondary
importance. Predatory bugs had a high activity in summer. Also, the aphelinid
parasite, Aphelinus mali (Haldeman), was observed with a high effectiveness at
late summer and at the end of the growing season.
