scholarly journals Influence of different oak species (Q. cerris L. and Q. robur L.) and environment conditions on the gypsy moth development

2005 ◽  
pp. 99-110 ◽  
Author(s):  
Slobodan Milanovic ◽  
Nenad Markovic

This paper presents the results of the laboratory study of gypsy moth development on Q. cerris and Q. robur foliage in controlled and uncontrolled environmental conditions. The survival is higher in controlled conditions than in uncontrolled conditions. In uncontrolled conditions, sex ratio is higher in individuals fed on pedunculate oak foliage (0.55) compared to those fed on Turkey oak foliage (0.39), while in the controlled conditions the situation is the opposite. The increase of in star number is greater in pedunculate oak than in Turkey oak. There is a statistically significant difference between the means of all the study characters (length of development of the first and the second instars, length of premarital development, number of instars and fecundity) in uncontrolled and controlled environmental conditions. Also, there is a statistically significant difference between the means of all the study characters on different oak species, except in fecundity. There is an interaction between environmental conditions and host plant species in the length of development of the first and the second instars, as well as in the number of instars during the development. The study results show that Turkey oak is more favorable for the gypsy moth development than pedunculate oak.

2002 ◽  
pp. 69-78
Author(s):  
Slobodan Milanovic

Gypsy moth (Lymantria dispar L) is the most significant pest of broadleaf forests. The dynamics of gypsy moth population depends on several biotic and abiotic factors, but it is also highly dependent on the quality of consumed food. The gypsy moth control increasingly relies on the biological preparations based on Bacillus thuringiensis subspec. kurstaki (Btk) and Lymantria dispar Nuclear Poliedrosis virus (NPV). Chemical preparations are still applied although more rarely, the pyrethroids which include also lambda-cyhalothrin This paper presents the study results of the effect of host plant on gypsy moth caterpillar (Lymantria dispar L) susceptibility to lambda cihalotrine insecticide, by which the study oak leaves were contaminated. The study results show the lowest mortality of the caterpillars fed on contaminated leaves of Turkey oak (17.5%), then pedunculate oak (86.1%), and the highest mortality of caterpillars fed on sessile oak leaves (92%). The rate of the gypsy moth caterpillar development depends on the host plant Susceptibility of the gypsy moth caterpillars to the above preparation depends on the host plant The knowledge of the effect of host plant on insecticide efficiency in gypsy moth suppression would render insecticide utilisation optimal.


2007 ◽  
pp. 55-67 ◽  
Author(s):  
Slobodan Milanovic

The development of Gypsy moth (Lymantria dispar L) was monitored in laboratory conditions, on the foliage of the species Quercus cerris L. Quercus petraea (Matt) Liebl. and Quercus robur L. The experiment was established in the controlled environmental conditions, at the temperature of 25?C, photoperiod 14:10 (day: night) and relative humidity 70%. The objective of the research was to determine the suitability of the study host plant species for gypsy moth development. The study results show that Gypsy moth caterpillars cultivated on Q. petraea foliage had a lower survival, higher number of moultings, longer preadult development and lower fecundity, which makes this species less suitable compared to the other two. Gypsy moth caterpillars cultivated on Q. cerris foliage had the highest survival degree the lowest number of moultings, the shortest preadult development and the highest fecundity, which makes this species the most favourable for gypsy moth development. Q. robur was between the former two species in this respect.


2010 ◽  
pp. 113-124 ◽  
Author(s):  
Slobodan Milanovic

In the establishment of mixed plantations, it is necessary to examine previously the relations of the principal and the admixed species and the most significant pests. This paper presents the results of the study of the gypsy moth caterpillar preference and performance on sweet chestnut and four oak species. Preference index is the highest for Hungarian oak (0.83) and Turkey oak (0.77), for sessile oak it is significantly lower (0.33), and for common oak it is equal to 0. In combination with sweet chestnut, the gypsy moth second-instar caterpillars prefer Hungarian oak, i.e. Turkey oak leaves. In combination with sessile oak or common oak, the gypsy moth caterpillars prefer sweet chestnut leaves. The analyzed parameters which characterise the performance of the gypsy moth fourth-instar caterpillars are lower for all study oak species compared to sweet chestnut, except in the case of Turkey oak. Based on the study results and the adopted principle that the mixture should be composed of the most favourable species, which will serve as the 'trap plant' during the gypsy moth outbreak, it can be concluded that Turkey oak is more favourable for the mixture with sweet chestnut than the other analyzed oak species.


2015 ◽  
Vol 61 (3) ◽  
pp. 143-148 ◽  
Author(s):  
György Csóka ◽  
Zoltán Pödör ◽  
Gyula Nagy ◽  
Anikó Hirka

AbstractWe investigated the canopy recovery of 3 tree species (pedunculate oak, Turkey oak, European beech) at two locations in the Veszprém county (Western Hungary) after severe defoliation by gypsy moth caterpillars in the spring of 2005. The Turkey oak has evidently the best recovery potential, and it almost completely replaced the lost foliage in 4 months. The pedunculate oak and beech needed 2 years to reach the same level of recovery. The pedunculate oak suffered from a heavy infection ofMicrosphaera alphitoidesafter defoliation and it probably slowed down its recovery. Neither the presence ofAgrilus biguttatusin the oak plot nor the appearance ofAgrilus viridisin the beech plot was observed during the study period. Population density of the buprestidCoraebus floerentinusshowed a considerable increase in the oak plot, but remained under the damage level. Neither other harmful appearance of other pests nor significant tree mortality were observed within 4 years from the defoliation. These results provide information for the evaluation of longer term influences of the gypsy moth defoliation and may support the decisions concerning pest control.


2006 ◽  
pp. 197-210 ◽  
Author(s):  
Slobodan Milanovic ◽  
Mara Tabakovic-Tosic ◽  
Nenad Markovic

The effect of two host plants, Turkey oak (Quercus cerris L) and black poplar (Populus nigra L) on gypsy moth (Lymantria dispar L) development was researched. The effect of host plant was determined based on the parameters which characterize the diet, growth and efficacy of conversion of ingested food of the third instar caterpillars. Along with the effect on development, the effect of host plant on the efficacy of biological preparation based on the bacterium Bacillus thuringiensis var. kurstaki in gypsy moth caterpillar suppression was also researched. The differences in parameters characterizing the diet, growth, and efficacy of ingested food between experimental groups of caterpillars grown on poplar and Turkey oak leaves are explained by the differences in the chemical composition of the leaves of these tree species. The efficacy of Btk preparation is conditioned by the mechanism and content of different groups of defense substances in the leaves of the applied tree species.


Author(s):  
Ma. Dulce C. Guillena

Gonado-somatic index and fecundity are tools for measuring the sexual maturity and ability of animals to reproduce.  This study investigates the reproduction of Trichiurus lepturus. Specifically, this aimed to determine the sex ratio, the GSI, the relationship between fecundity and total length, fecundity and total weight, fecundity and ovary weight. The Descriptive Method of research was used.  Percentage and chi-square was utilized in determining the percentage of occurrence and sex ratio respectively.   Pearson r Product Moment Coefficient of Correlation was used to determine the relationships of the parameters. The study revealed that females outnumbered males and the sex ratio for different month showed significant difference.  Spawning season was observed to occur in November and December as revealed in its GSI values and it synchronized with the full and new moon phases.  Fecundity is positively correlated with body weight, body size, and ovary weight where ovary weight is observed to be the best index for fecundity.  The results of this study could be used further for formal stock assessment of cutlassfish fishery.


2020 ◽  
Vol 66 (1) ◽  
pp. 19-22
Author(s):  
Melania Macarie ◽  
Simona Maria Bataga ◽  
Monica Pantea ◽  
Razvan Opaschi ◽  
Simona Mocan ◽  
...  

AbstractObjective: This study aims to determine the correlation between risk factors and erosive esophagitis development.Methods: We conducted a retrospective observational study on a consecutive series of 19.672 patients who underwent upper gastrointestinal endoscopy between 01.01.2011-31.12.2017. A total of 3005 patients, diagnosed with erosive esophagitis, were included in the present study and stratified according to Los Angeles classification.Results: During the studied period we found 3005 patients with erosive esophagitis, sex ratio male to female was 1.3/1, the most common forms of esophagitis being grade A and B: 74.54% patients with esophagitis grade A, 14.80% patients with grade B; 5.29% patients were with grade C and 5.35% patients with esophagitis grade D. In severe esophagitis the male predominance was more prevalent (249 males, 71 female), with a sex ratio 3.50/1. The correlation of male gender with severe esophagitis was highly statistically significant (p < 0.0001, OR 2.97; 95% CI 2.25-3.91). Hiatal hernia was diagnosed in 1171 patients, the presence of large hiatal hernias, being an important predictor, with statistical significance (p < 0.0001, OR 3.41; 95% CI 2.22-5.21), for severe esophagitis development. Incidence of Helicobacter pylori infection was 11.51%, in the entire study group, with no statistical significant difference between patients with mild or severe esophagitis (12.02% vs 7.18%).Conclusion: Erosive esophagitis is a frequent disease, the most common forms being grade A and B. Male gender and the presence of hiatal hernia are the most important risk factors for erosive esophagitis development, in our study group.


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