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English :
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Effects of application of selected insect growth regulators and plant extracts on some physiological aspects of the blackcut worm, Agrotis ipsilon (Huf.)
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Arabic :
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أثر استخدام منظمات نمو حشرية ومستخلصات نباتية مختارة على بعض النواحى الفسيولوجية للدودة السوداء القارضة أجروتيس إبسيلون(هوف.)
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| Abstract |
The effects of the juvenile hormone analogue (pyniproxyfen) the chitin synthesis inhibitor (flufenoxuron) and the acetone extract of Melia azedarach seeds on certain biological, physiological and histological aspects of Agrotis ipsilon (Huf.) were studied. Treatment with these compounds was carried out on the 4th instar larvae, and the latent effects were investigated on the late 6 th instar larvae. Results are summarized as follows:
1- Susceptibility test
i) The susceptibility of A. ipsilon larvae to the tested compounds increased by increasing the concentration at all the tested temperatures (20, 25, 30°C). However, the highest mean of means of larval mortality was obtained at 25°C.
ii) The obtained LC50 values indicated that the toxicity of the tested compounds significantly increased with increasing the temperature up to 25°C, then significantly decreased by rising the temperature to 30°C, i.e., the toxicity of the tested compounds displayed bimodal temperature coefficient.
iii) Pupation and adult emergence were reduced as a result of larval treatment.
iv) Based on LC50 values, flufenoxuron was the most toxic compound followed by pyriproxyfen; whereas the plant extract was much less effective.
2) Biological effects:
i) Treatment with pyriproxyfen significantly increased the larval duration in the parental (P), first (F1) and second (F2) filial generations as compared to the control. On the contrary, treatment with flufenoxuron or the plant extract significantly decreased the larval duration in the P, F1 and F2 filial generations.
ii) Pupal duration was significantly increased with pyriproxyfen treatment in the P, F1 and F2 filial generations. While, flufenoxuron insignificantly decreased the pupal duration in the parental generation and insignificantly increased the pupal duration in both F1 and F2 filial generations. On the other hand, the plant extract significantly decreased the pupal duration of parental generation and insignificantly decreased the pupal duration of F, generation.
iii) Pupal weight was significantly decreased with flufenoxuron treatment in parental, F1 and F2 filial generations. However, treatment with pyriproxyfen did not affect the pupal weight in the first and second filial generations. On the other hand, treatment with the plant extract insignificantly decreased the pupal weight in both the first and second filial generations; while a significant decrease was recorded in the parental generation.
iv) Adult longevity of both sexes was significantly decreased, during the three generations.
v) In all mating combinations, the fecundity was significantly decreased especially for treated females mated with treated males. The egg-hatchability percent was significantly decreased. This reduction was more obvious in case of flufenoxuron treatment than in case of the plant extract and pyriproxyfen. This was also followed for the percentage of sterility.
vi) The three tested compounds exhibited some morphogenetic effects such as larval, pupal and adult deformities, as well as larval-pupal intermediates. More morphogenetic efficiency was obtained in case of flufenoxuron and pyriproxyfen treatment than in case of the plant extract treatment.
3) Physiological effects:
i) Treatment with pyriproxyfen and flufenoxuron significantly increased and decreased acid and alkaline phosphatase activities, respectively. While, the plant extract insignificantly decreased their activities.
ii) The three tested compounds significantly decreased the transaminases activity.
iii) Treatment with pyriproxyfen significantly increased amylase activity; while flufenoxuron and the plant extract insignificantly increased its activity.
iv) Invertase activity was insignificantly increased following treatment with pyriproxyfen and flufenoxuron. On the other hand, the plant extract significantly decreased invertase activity.
v) Both pyriproxyfen and the plant extract significantly decreased trehalase activity; while flufenoxuron insignificantly decreased trehalase activity.
vi) Total lipids, proteins and carbohydrates were significantly decreased following treatment with both pyriproxyfen and plant extract; while flufenoxuron insignificantly decreased the total lipids and carbohydrates and significantly decreased total proteins.
4) Blood picture:
i) There was a difference in the mean total haemocyte counts among the three tested compounds. Both flufenoxuron and the plant extract significantly increased the total haemoctye counts; while pyriproxyfen significantly decreased such counts.
ii) Both pyriproxyfen and flufenoxuron significantly increased the viability of haemocytes. On the other hand, the plant extract insignificantly increased such viability.
iii) Five types of haemocytes could be recognized in the haemolymph of
A. ipsilon larvae: prohaemocytes, plasmatocytes, granulocytes, spheuulocytes and oenocytoids.
iv) Pyriproxyfen increased all types of haemocytes, except for significantly decreased in plasmatocytes and insignificant decreased in spherocytes.
v) Flufenoxuron significantly increased all types of haemocytes, except for insignificant increased spherulocytes and significantly decreased plasmatocytes.
vi) The plant extract significantly decreased prohaemocytes, spherocytes and oenocytes. On the contrary, it significantly increased the plasmatocytes and granulocytes.
5) Histological effects
i) Treatment of A. ipsilon larvae with the LC50 of pyriproxyfen did not affect the cuticle. It caused vacuolization of the hypodermis and clumping of the nuclear chromatin.
ii) Treatment with the LC50 of flufenoxuron more or less completely disrupted the formation of endocuticle, leaving only very few fragments. The hypodermis was not clearly affected.
iii) Treatment with the LC50 of acetone extract of M. azedarach seeds caused a slight disruption to the cuticle. The hypodermis was highly vacuolated and the nuclei were either degenerated or pycnotic. The magnitude of the cuticular disruption in this case was comparatively lower than that of flufenoxuron treatment.
iv) Treatment of A. ipsilon larvae with LC 50 of pyriproxyfen caused vacuolization of the circular muscle layer of the midgut and rupture of the longitudinal one. The columnar epithelial cells were vacuolated and the striated border was broken. Some of thenuclei were sloughed off into the disrupted peritrophic membrane.
v) Treatment with the LC50of flufenoxuron caused exfoliation of the midgut epithelium from the underlying muscle fibers, leaving a large vacuole or space. Vacuolization of the midgut epithelium and disruption of both the peritrophic membrane and the striated border were evident. The nuclei of the columnar cells were pycnotic, some of the degenerated columnar cells were fused with the disrupted peritrophic membrane, and few pycnotic free nuclei were found floating in the lumen mixed with the peritrophic membrane. The lumen of the gut was collapsed, globular bodies and cytoplasmic fragments were seen pinching off or exuding from the tip of some epithelial cells within the lumen vicinal to the deteriorated peritrophic membrane.
vi) Treatment with the LC50of acetone extract of M. azedarach seeds induced vacuolization of the midgut epithelium. The peritrophic membrane was fragmented together with obliteration of the striated border (microvilli). The circular muscle layer lost its compact appearance and the longitudinal one was vacuolated and the lumen became shrinked. Globular bodies were exuded from the tip of epithelial cells and mixed with the disrupted peritrophic membrane, and the nuclei showed pycnosis.
Finally it could be recommended that the chitin synthesis inhibitor, flufenoxuron and the acetone extract of M. azedarach seeds stimulated efforts to use them in combating the population of A. ipsilon.
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| Publication year |
2002
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| Availability location |
7 ش نادى الصيد- معهد بحوث وقاية النباتات
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| Availability number |
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| Organization Name |
Plant Protection Research Institute (PPRI)
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| Country |
Egypt
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| Publisher |
Name:
قسم علم الحشرات كلية العلوم- جامعة عين شمس
Place:
كلية العلوم- جامعة عين شمس
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| Author(s) from ARC |
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| Agris Categories |
Pests of plants
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AGROVOC
TERMS |
Agrotis ipsilon.
Flufenoxuron.
Insect growth regulators.
Melia azedarach.
Plant extracts.
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| Publication Type |
PhD Thesis
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