Authors:H. Bu, X. Chen, Y. Wang, X. Xu, K. Liu, and G. Du
In this paper, 633 species (involving 10 classes, 48 families, 205 genera) collected from the alpine meadow on the eastern Qinghai-Tibet plateau were studied. We tested potential factors affecting variation in mean germination time (MGT), i.e., plant traits (adult longevity, dispersal mode and seed size) or phylogeny, to evaluate if these factors were independent or they had interaction. Nested ANOVA showed that taxonomic membership accounted for the majority of MGT variation (70%), and in the generalized linear model, family membership could explain independently the largest proportion of MGT variation (29%). The strong taxonomic effect suggests that MGT variation within taxonomic membership is constrained. The other plant traits could also explain MGT variation independently (1% by adult longevity and dispersal mode, respectively, and 2% by seed size). Thus, the phylogeny was an important constraint to maintain the stability of species, and we could simplify the question if we regarded the phylogeny as an individual factor, but we could not negate the adaptive significance of the relationship between other plant traits and seed MGT. In addition, a large percentage of the variance remained unexplained by our model, thus important selective factors or parameters may have been left out of this analysis. We suggest that other possible correlates may exist between seed germination time and additional ecological factors (for example, altitude, habitat and post-dispersal predation) or phylogenetic related morphological and physiological seed attributes (e.g., endosperm mass) that were not evaluated in this study.
Authors:F. Momen, A. Metwally, A. Nasr, I. Ebadah, and K. Saleh
Eight phytoseiid species were tested to evaluate their potential as predators of Tuta absoluta (Meyrick) eggs as an alternative/natural food source under laboratory conditions. Predatory phytoseiid mites were, namely: Typhlodromips swirskii (Athias-Henriot), Euseius scutalis (Athias-Henriot), Cydnoseius negevi (Swirski and Amitai), Neoseiulus barkeri (Hughes), Neoseiulus californicus (McGregor), Phytoseius finitimus Ribaga, Proprioseiopsis badri (Yousef and El-Borolossy) and Amblyseius largoensis (Muma).Immatures survival of tested phytoseiid species were low on eggs of T. absoluta and all failed to develop to adulthood.Adult females of C. negevi, A. largoensis and N. barkeri were able to feed and sustain oviposition on eggs of T. absoluta. A diet of insect eggs provided the shortest oviposition period and adult longevity of C. negevi, while A. largoensis showed the longest corresponding periods. The total and daily number of insect eggs consumed was significantly higher in N. barkeri and C. negevi than in A. largoensis. Similarly N. barkeri laid significantly higher number of eggs (47.39 eggs/female) than that deposited by C. negevi and A. largoensis (41.0 and 30.7 eggs / female). The sex ratio of the progeny was strongly female biased and ranged: (females/total=61.8−75.4%) when insect eggs were provided for C. negevi, N. barkeri and A. largoensis.Survival of adult females of T. swirskii, P. badri, N. californicus, E. scutalis and P. finitimus were low on T. absoluta eggs and all died within 2–4 days.
Authors:A. M. Metwally, F. M. Momen, A. K. Nasr, A. A. Abdallah, I. M. Ebadah, and Kh. M. Saleh
Tomato crop in the Mediterranean Basin has been recently affected by the exotic pest Tuta absoluta (Meyrick), which is difficult to control due to its high reproduction rate and potential to develop resistance to insecticides. In this paper, the suitability and effectiveness of three predatory phytoseiid mites Cydnoseius negevi (Swirski and Amitai), Neoseiulus barkeri (Hughes) and Amblyseius largoensis (Muma), an indigenous species, were evaluated on larvae of T. absoluta under laboratory conditions. First instar larvae of T. absoluta proved to be possible food source for tested phytoseiid mites under laboratory conditions.
Females of C. negevi, A. largoensis and N. barkeri were able to feed and sustain oviposition on unfed, first instar larvae of T. absoluta. A diet of insect larvae provided the shortest oviposition period and adult longevity of C. negevi and A. largoensis, while N. barkeri showed the longest corresponding periods. The total and daily number of insect larvae consumed was significantly higher in N. barkeri than in A. largoensis and C. negevi. Likewise, N. barkeri laid significantly higher number of eggs (23.6 eggs / female) than that deposited by C. negevi and A. largoensis (2.5 and 3.9 eggs / female). The sex ratio of the progeny was female biased and ranged: (females / total=0.62-0.68%) when insect larvae were provided for females of C. negevi, A. largoensis and N. barkeri.
Authors:M. F. Hassan, F. M. Momen, A. K. Nasr, A. H. Mabrouk, and M. M. Ramadan
The laelapid mites Cosmolaelaps keni and Laelaspis astronomicus beside the rhodacarid mite Protogamasellopsis denticus are biological control agents and being native predators in Egypt. In order to raise active population of above species, the biology and demographic parameters, of the three tested species were observed under laboratory conditions with eggs of Ephestia kuhniella. All predatory species were developed and reproduced with E. kuhniella eggs. The mean developmental and oviposistion periods of L. astronomicus females were the longest from the other tested species. The mean longevity of C. keni was longer than that of P. denticus. Cosmolaelaps keni consumed more E. kuhniella eggs during the oviposition and adult longevity periods than other species did. Protogamasellopsis denticus fed on E. kuhniella food gave the most rate of oviposition as shown by the maximum fertility, net reproductive rate and gross reproductive rate. Laelaspis astronomicus preying on E. kuhniella eggs gave the longest generation time, lowest rate of fecundity and all life table parameters compared to other tested species; therefore E. kuhniella eggs was appropriate for the oviposition of P. denticus and C. keni rather than L. astronomicus.
This study is the first to report that E. kuhniella eggs were an acceptable factitious food for P. denticus, L. astronomicus and C. keni.
Authors:F. M. Momen, A. S. Metwally, A. K. Nasr, M. Gesraha, Y. A. Mahmoud, and K. H. M. Saleh
The predatory mite Cosmolaelaps keni is a native laelapid mite in Egypt. Development and adult longevity durations as well as fecundity of C. keni reared on five types of prey, Bactrocera zonata, Spodoptera littoralis and Corcyra cephalonica eggs (as insects prey), Aceria dioscoridis and Caloglyphus rodriguez (as mites prey) were determined under laboratory conditions. Cosmolaelaps keni was able to feed, develop and sustain oviposition on all examined insect and mite species. The mean developmental period of C. keni on B. zonata and S. littoralis eggs was significantly shorter than those fed C. cephalonica eggs and both mite species. Deutonymphs of C. keni were consumed similar number of insect eggs, while during the oviposition period, more B. zonata eggs were consumed. A diet of C. rodriguez provided the shortest oviposition period and longevity, while C. cephalonica eggs showed the longest period in this respect. During the oviposition period, preying on B. zonata and C. cephalonica eggs gave the highest fecundity rates for the predatory mite compared to S. littoralis and C. rodriguez. The sex ratio of C. keni progeny was in female-biased. Bactrocera zonata eggs as a prey gave the highest rate of oviposition as shown by the maximum fertility, net reproductive rate and gross reproductive rate as well as the shortest generation time compared to other tested prey; therefore B. zonata eggs were appropriate factitious prey for oviposition and mass rearing of the predatory mite C. keni.
Aphids have acquired the status of major pest in North-western plains of India. A complex of five species infests the wheat in this part of the country. The diatomaceous earth (DE) has the potential to substitute the most widely used method of chemical control. Laboratory and field investigations were conducted to evaluate the effectiveness of DE either as soil or foliar application for suppression of wheat aphids during 2013–2014 and 2014–2015. The fecundity, adult longevity and total developmental duration of Rhopalosiphum padi decreased with the increasing dosage of soil application of DE in laboratory evaluation. However in field studies, no significant difference in aphid population was observed among different levels of DE application in soil. Foliar application of DE 150 kg/ha and higher dosages significantly reduced aphid population for initial two days but thereafter it had no effect on aphid prevalence. Wheat plant dusted with different dosages of DE did not show any visible injury but the reduction in chlorophyll content was observed in them. Overall, poor field efficacy coupled with loss of chlorophyll and safety issues relating to foliar application of DE proved against its use for control of sucking insect pests.
Authors:Ismail Abdullahi, G. A. I. Atiri, G. O. Dixon, and et al.
Powell, D. A., Bellows, T. S. Jr. 1992: Adultlongevity, fertility and population growth rates for Bemisia tabaci (Genn) (Homoptera, Aleyrodidae) on two host plant species. Journal of Applied Entomology , 113 , 68-78.