scholarly journals Host plant effect on the susceptibility of gypsy moth caterpillars to insecticides

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.

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.


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.


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.


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.


2012 ◽  
pp. 127-138
Author(s):  
Slobodan Milanovic ◽  
Sladjan Milanovic

The effect of four oak species: Turkey oak, Hungarian oak, sessile oak and English oak on the number of moultings and head capsule width of the gypsy moth caterpillars was researched. Host plants have a statistically significant effect on the number of both male and female larval instars. The highest number of larval instars was recorded for caterpillars fed on sessile oak leaves, and the lowest number was recorded for those fed on Turkey oak leaves. Females reared on Hungarian oak and English oak leaves had a normal number of larval instars. Except for 1st instar caterpillars, all other larval instars showed a statistically significant host plant effect on the head capsule width. The widest head capsules were found on caterpillars fed on Turkey oak leaves, and those fed on sessile oak leaves had the narrowest head capsules. The study data on head capsule widths can be practically applied in the determination of the optimal ratio of larval instars in the gypsy moth population, i.e. in the determination of terms for aerial spraying actions.


2008 ◽  
pp. 127-142 ◽  
Author(s):  
Slobodan Milanovic ◽  
Jelica Lazarevic ◽  
Marija Mrdakovic ◽  
Milena Vlahovic ◽  
Zoran Miletic

Insect growth and development depend on nutritive value and secondary metabolite content of their host plants. This influence may be exerted through changing the activity of digestive enzymes which further affects efficiency of conversion of ingested food. This paper represents the results of investigation of feeding effects on the leaves of three oak species (Quercus cerris, Q. robur and Q. petraea) on growth, development and digestive enzyme activities of the 4th instar gypsy moth larvae (Lymantria dispar L.). Compared to larvae fed on Q. cerris and Q. robur leaves, larvae fed on Q. petrea exhibited the lowest body mass, midgut protein content and specific protease activity. Specific amylase activity was significantly reduced in the midguts of larvae fed on Q. robur while host plant did not affect larval duration upon molting into the 4th instar. Concomitant chemical analyses of leaves given to the 2nd and 4th instar larvae was carried out in order to explain the obtained results.


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