Abstract: Integrated Pest Management (IPM) aims to combine biological and chemical strategies and measures, hence highlighting the study of acute toxicity and sub-lethal effects of pesticides comprehensively. The present research focused on the side effects of thiamethoxam and pirimicarb sub-lethal concentrations on demographic parameters of Diaeretiella rapae (McIntosh Laboratory) (Hymenoptera: Braconidae). Adult parasitoids were exposed to LC25 of insecticides as well as distilled water as the control. The results showed that thiamethoxam adversely affected population parameters (r, λ, R0, T), adults' longevity, females' oviposition period and mean fecundity, and a similar trend was obtained for pirimicarb with the exception of generation time (T), the latter did not significantly change compared to the control. The intrinsic rate of increase (r) in the control and those treated with pirimicarb and thiamethoxam were 0.2801, 0.2064, 0.1525 days-1, respectively, and the sex ratio was biased toward females in all treatments. Furthermore, none of the insecticides influenced total pre-oviposition period (TPOP) and offspring emergence rate. In general, these results indicated that both insecticides potentially distort the demographic parameters of the parasitoid even at sub-lethal concentrations, and then they should not be considered for IPM program in the presence of D. rapae.
Abstract: The olive fruit fly, Bactrocera oleae Gmelin (Diptera: Tephritidae), is one of the most serious pests in olive orchards in growing province in Iran. The female lay eggs in green olive fruit and larvae hatch inside the fruit, where they feed upon the fruit matters. One of the main ecologically friendly and species-specific systems of pest control is the sterile insect technique (SIT) which is based on the release of large numbers of sterilized insects. The objective of our work was to develop a SIT against B. oleae by using of gamma radiation for the laboratory and field trial in Iran. Oviposition of female mated by irradiated males is one of the main parameters to determine achievement of SIT. To conclude the sterile dose, pupae were placed under 0 to 160 Gy of gamma radiation. The main factor in SIT is the productivity of females which are mated by irradiated males. The emerged adults from irradiated pupae were mated with untreated adults of the same age by confining them inside the transparent cages. The fecundity of the irradiated males mated with non-irradiated females was decreased with the increasing radiation dose level. It was observed that the number of eggs and also the percentage of the egg hatching was significantly (P < 0.05) affected in either IM x NF crosses compared with NM x NF crosses in F1 generation at all doses. Also, the statistical analysis showed a significant difference (P < 0.05) in the mean number of eggs laid between irradiated and non-irradiated females crossed with irradiated males, which suggests that the males were susceptible to gamma radiation. The egg hatching percentage declined markedly with the increase of the radiation dose of the treated males in mating trials which demonstrated that egg hatch rate was dose dependent. Our results specified that gamma radiation affects the longevity of irradiated B. oleae larvae (established from irradiated pupae) and significantly increased their larval duration. Results show the gamma radiation, and SIT can be used successfully against olive fruit flies.
Abstract: Citrus leaf miner (Phyllocnistis citrella Stainton) is native to Asia and one of the most serious pests of Iran’s citrus nursery stocks. In the present study, the possibility of insect mass rearing on four various citrus hosts and the effects of gamma irradiation on the pupal mortality and reproduction of this pest were studied. Trifoliate orange and grapefruit showed less infection, while the number of pupae in Valencia oranges and sweet lemons cages was so high. There was not any significant difference between weight of male and female pupae among different citrus hosts, but generally the weight of male pupae was less than females. Use of Valencia orange or sweet lemons seedlings in especial dark emergence and oviposition cages could be recommended for mass rearing of this pest. In this study, the effects of gamma radiation at doses 100 to 450 Gy on biological and reproductive parameters of the pest has been determined. The results show that mean percent of pupal mortality increased with increasing doses and reached to 28.67% at 450 Gy for male pupae and 38.367% for female pupae. Also, the mean values of this parameter were higher for irradiated female, which indicated the higher sensitivity of this sex. The gamma ray irradiation from 200 and 300 Gy caused decrease in male and female adult moth longevity, respectively. The eggs were laid by emerged females, and their hatchability was decreased by increasing gamma doses. The fecundity of females in both combinations of crosses (irradiated male × normal female and irradiated female × normal male) did not differ, but fertility of laid eggs by irradiated female × normal male affected seriously and the mean values of this parameter reached to zero at 300 Gy. The hatchability percentage of produced eggs by normal female × irradiated male at 300 Gy was 23.29% and reached to less than 2 % at 450 Gy as the highest tested dose. The results of this test show that females have more radio-sensitivity in comparison to males.
Abstract: In present study, it was aimed to evaluate the gamma radiation impacts on tomato leaf miner at different biological stages. The laboratory colony of tomato leaf miner was used to set up the experiments. Different biological stages of the insects (eggs, 4th instars and pupae) were irradiated using Cobalt-60 at doses of 0 (control), 100 Gray (Gy), 200 Gy, 300 Gy and 400 Gy in Cos-44HH-N source, at dose rate of 480 Gy/h. After irradiation, the eggs were incubated until hatching; the mature larvae were reared to complete their developments. Adult emergences from irradiated pupae were also evaluated. The results showed that there were no egg hatching at all tested irradiation doses. Although, the pupal percentages of irradiated mature larvae were 54%, 15% and 8% at doses of 100 Gy, 200 Gy and 300 Gy respectively, there were no adult emergences from irradiated mature larvae. On the other hand, the adult emergences were observed from irradiated pupae, decreased as radiation doses increased along with malformed adult appearance. Male and female individuals were out crossed with laboratory reared adults. Fecundity was correlated with radiation doses.
Abstract: In this study, breeding biology and induced breeding
of freshwater mud eel, Monopterus cuchia was observed during the
experimental period from February to June, 2013. Breeding biology
of freshwater mud eel, Monopterus cuchia was considered in terms of
gonadosomatic index, length-weight relationship of gonad, ova
diameter and fecundity. The ova diameter was recorded from 0.3 mm
to 4.30 mm and the individual fecundity was recorded from 155 to
1495 while relative fecundity was found from 2.64 to 12.45. The
fecundity related to body weight and length of fish was also
discussed. A peak of GSI was observed 2.14±0.2 in male and 5.1
±1.09 in female. Induced breeding of freshwater mud eel,
Monopterus cuchia was also practiced with different doses of
different inducing agents like pituitary gland (PG), human chorionic
gonadotropin (HCG), Gonadotropin releasing hormone (GnRH) and
Ovuline-a synthetic hormone in different environmental conditions.
However, it was observed that the artificial breeding of freshwater
mud eel, Monopterus cuchia was not yet succeeded through inducing
agents in captive conditions, rather the inducing agent showed
negative impacts on fecundity and ovarian tissues. It was seen that
mature eggs in the oviduct were reduced, absorbed and some eggs
were found in spoiled condition.
Abstract: In the present study fecundity of Terapon jarbua was estimated for 41 matured females from the Bay of Bengal, Pondicherry. The fecundity (F) was found to range from 13,475 to 115,920 in fishes between 173-278mm Total length (TL) and 65- 298 gm weight respectively. The co-efficient of correlation for F/TL (log F = - 4.821 + 4.146 log TL), F/SL (log F = -3.936 + 3.867 log SL), F/WF (log F = 1.229 + 0.730 log TW) and F/GW (log F = 0.724 + 1.113 log GW) were obtained as 0.474, 0.537, 0.641 and 0.908 respectively. The regression line for the TL, SL, WF and GW of the fishes were found to be linear when they were plotted against their fecundity on logarithmic scales. Highly significant (P
Abstract: Scolothrips longicornis Priesner is one of the
important predators of tetranychid mites with a wide distribution
throughout Iran. Life table and population growth parameters of S.
longicornis feeding on two-spotted spider mite, Tetranychus
turkestani Ugarov & Nikolski were investigated under laboratory
condition (26±1ºC, 65±5% R.H. and 16L: 8D). To carry of these
experiments, S. longicornis collections reared on cowpea infested
with T. turkestani were prepared. The eggs with less than 24 hours
old were selected and reared. The emerged larvae feeding directly on
cowpea leaf discs which were infested with T. turkestani. Thirty
females of S. longicornis with 24 hours age were selected and
released on infested leaf discs. They replaced daily to a new leaf disc
and the laying eggs have counted. The experiment continued till the
last thrips had died. The result showed that the mean age mortality of
the adult female thrips were between 21-25 days which is nearly
equal life expectancy (ex) at the time of adult eclosion. Parameters
related to reproductive table including gross reproductive rate, net
reproductive rate, intrinsic rate of natural increase and finite rate of
increase were 48.91, 37.63, 0.26 and 2.3, respectively. Mean age per
female/day, mean fertile egg per female/day, gross hatch rate, mean
net age fertility, mean net age fecundity, net fertility rate and net
fecundity rate were 2.23, 1.76, 0.87, 13.87, 14.26, 69.1 and 78.5,
respectively. Sex ratio of offspring also recorded daily. The highest
sex ratio for females was 0.88 in first day of oviposition. The sex
ratio decreased gradually and reached under 0.46 after the day 26 and
the oviposition rate declined. Then it seems that maintenance of
rearing culture of predatory thrips for mass rearing later than 26 days
after egg-laying commence is not profitable.
Abstract: The study aimed to evaluated the reproductive performance response to short term oestrus synchronization during the transition period. One hundred and sixty-five indigenous multiparous non-lactating goats were subdivided into the following six treatment groups for oestrus synchronization: NT control Group (N= 30), Fe-21d, FGA vaginal sponge for 21days+eCG at 19thd; FPe- 11d, FGA 11d + PGF2α and eCG at 9th d; FPe-10d, FGA 10d+ PGF2α and eCG at 8th d; FPe-9d, FGA 9d +PGF2α and eCG at 7thd; PFe-5d, PGF2α at d0 + FGA 5d + eCG at 5thd. The goats were natural mated (1 male/6 females). Fecundity rates (n. births /n. females treated x 100) were statistically higher (P < 0.05) in short term FPe-9d (157.9%), FPe- 11d (115.4%), FPe-10d (111.1%) and PFe-5d (107.7%) groups compared to the NT control Group (66.7%).