A research was conducted in Yasouj region to determine population dynamics of the GYPSY MOTH in 2006 and 2007. Also it was aimed to calculate the correlation coefficient between the population densities of 2006 and 2007, in order to build a predictive model for the pest. The number of overwintering egg masses was counted during the winter months in ten different orchards. The number of egg masses of the pest was recorded at weekly intervals in ten orchards during the growth seasons in 2006 and 2007. Results indicated that the egg mass densities were 1.71 ± 0.2 and 2.88 ± 0.3 per fifty squares meter and 342 ± 22 and 576 ± 37 egg masses per hectare in winters 2006 and 2007, respectively. Regression analysis of the pest population density in 2006 and 2007 indicated that only 32.37% of the 2007 population variance could be accounted for the population density in 2006. It was obvious that more than 68% of the population changes are under the influence of unknown biotic and abiotic environmental factors.

Lymantria disparL. distinguished GYPSY MOTH outbreak at the forest surroundings of natural resources factually of Tarbiat Modarres University, beside of Noor forest park than that is one of the remaining plain forest of north forest of Iran, in 2001. The Polyphage larval of this pest by high crowd density attacked the trees and feed whole crown of them. It phenomenon shaped summer landscape of this forest similar to autumn fall. This pest passes over winter in the egg masses. In late March to early April synchronized budding of trees the larvae begin to hatch. Larvae after passing five (at male) and six (at female) larval instars enter the pupae stage. The adult insects (MOTHs) emerge in late June. MOTH after emerging mating then female lays the egg masses immediately. After 20 to 30 days embryos develop into larvae at the egg masses and the larvae remain in the eggs during the winter. The results of 100% inventory show The most damages was in Prunus persica, Parrotia persica, Quercus castaneaefolia, Carpinus betulus, Pterocaria fraxinifolia, Populus caspica, Ulmus carpinifoliaand Alnus glutinosatree species respectively. There was not any damage in Diospyrus lotus, Morus alba andFicus carica tree species. In the study natural controlling of this pest Bacillus thuringiensis bacteria and Calosoma sycophanta ground beetle as natural enemy and predators were reported in the study area that they had important role in decrease of Lymantria disparpopulation.

GYPSY MOTH, Lymanatria dispar L.(Lep., Lymantriidae), which is a polyphagous and dangerous pest, is spread in different areas of Arasbaran forests and feed on many species of trees and shrubs specially oak trees. The pest overwinters with egg stage in Arasbaran. First instar larvae emerge gratually from egg masses depend on c1imat and latitude of different areas from early spring of next year. The young larvae after lasting 4 instar (for males) or 5 instar (for females) transform to pupa in folds of leaves or trunk of host plants. From late july the MOTHs come out of the cocoons and mate. Then the female MOTH lays her eggs after 3 to 4 days of emerging. The fall and winter passed in the egg stage. There is only 1 generation per year. Following three parasitoid wasps and one parasitoid nematode are obtained in the natural enemies study of the pest. 1) A parasitoid nematode (Mermithidae) destroyed the last instars of larvae, it probably is belong to Hexamermis genus. 2) Monodontomerus aereus Walker (Torymidae) 3) Glyptapanteles porthetriae Mues.(Braconidae) 4) Glyptapanteles indiensis Marsh (Braconidae) Three last mentioned species that they parasitize on pupa(No.2)and larvae (No.3 and 4), are reported for the first time from Iran. Also all of natural enemies are new records on the pest.  

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Using pheromone traps is one of the suitable methods for monitoring and control of forest pests. The objective of this research was to determine the effects of atmospheric conditions and daily times on pheromone traps efficiency of the GYPSY MOTH, Lymantria dispar (L.). Sampling was carried out in Daland forest park during 2008. Samples were taken on three atmospheric conditions (sunny, cloudy and rainy) and daily times (07:00 AM, 08:00 PM and 01:00 PM). A factorial experiment in a randomized design was used to analyze the data and means were compared using Duncan’s multiple range test. Eight white traps were placed on trees at distance of 100-150 m from each other at 1.5 m height in each site. Results showed that atmospheric conditions and daily times of day had significant (P<0.001) effects on number of males capture in pheromone traps. The interaction of daily times and atmospheric conditions were also significant. Maximum captures of male MOTHs were observed at 07:00 AM, and sunny conditions. Also, minimum captures occurred in 08:00 PM and rainy conditions.

The GYPSY MOTH, Lymantria dispar (Lepidoptera: Lymantriidae) is one the most destructive defoliator pest of forests across world. The present study is the first report of outbreak and damage of this pest in Northern Zagros forests based on the field observations, sampling and laboratory assays to confirm the identification. In spring the larvae specimens were collected on the Oak (Quercus brantii, Q. infectoria, Q. libani) and other forest trees and shrubs. In order to rapid and accurate identification of the pest, DNA extraction and PCR amplification of the COI gene fragment was performed for ten specimens including eggs, larvae and adults, followed by sequencing of two larvae specimens. The Blast results revealed that two sequences belong to L. dispar species with 99-100% similarity to other GenBank sequences. However, this species is not established yet in many western forests of Iran. But, due to the potential threats of the pest for the forest ecosystems and its widely flying activity, immediate action and efforts must be taken to control the pest population.

The GYPSY MOTH, Lymantria dispar (L.), is one of the most important pests of forest trees throughout the world. Larval herbivory can result in leaf area reductions, leaves abscission, and eventually, yield quality and quantity losses. The objective of this research was to determine the effects of oviposition height and host tree species on some biological parameters of GYPSY MOTH, including egg clutch size, egg hatching percent, larval body length and mortality percent of first instars. Sampling was carried out in Daland forest park (Infestation foci in Golestan province) during 2008 and 2009. Samples were taken on five oviposition heights (0.5, 1, 1.5, 2, and 2.5 m) on trunk of four common host species including, Zelkova carpinifolia, Parrottia persica, Quecrus castanifolia and Carpinus carpinifolia. A factorial experiment in a randomized design was used to analyze the data and means were compared using Duncan’s multiple range test. Results showed that the oviposition heights significantly affected pest biological parameters, but the effects of host tree species and interacting effects were not significant. The highest survival percent, egg clutch size and body length was observed at oviposition height of 0.5 m on the Parrottia persica species, and the most larval mortality of first instars was recorded at oviposition height of 2.5 m on the Quecrus castanifolia species.

The GYPSY MOTH, Lymantria dispar L. (Lep., Lymantriidae) is one of the most destructive pests of forest shrubs and trees throughout the Arasbaran region (East Azarbaidjan, Iran). The pest causes serious periodical damage on its host plant species, especially oak trees. In this study, the effects of two formulations of Bacillus thuringiensis containing Btk (commercial product Dipel) and BtH (made in Iran) were evaluated on GYPSY MOTH larvae. Results showed that there was a significant difference between Dipel and BtH. Dipel (1.2 g/L) and BtH (6 g/L) treatments caused maximum mortality 29.23% and 23.05%, respectively and 1.2 g/L dosage of BtH with average 13.61% caused the less mortality on the pest larvae. Mean comparison of L. dispar larvae mortality in different times after treatments (for both formulations) indicated that there was no significant difference between 1 and 3 days, but difference between those two mentioned days with 7 and 14 days was significant, so that the treatment effect increased with time. By comparing the number of parasitoid wasp and nematode emerged from treated survived larvae, the treatments effects on natural enemies was quite evident. Natural enemies emerged from larvae treated by 1.2 g/L, 3 g/L and 6 g/L dosage of BtH and Dipel were reduced 12.3, 34.7, 59.8 and 81.6 percent, respectively in comparison to control. In other words, by increasing the effectiveness of Bt treatments, the possibility of natural enemies emergence was reduced. In this regard, high concentrations of BtH and Dipel have the most impact in reduction of natural enemies emerging. Assessment of larval feeding on the treated leaves revealed that because of the rapid effects of Bt to 2nd instar larvae, there was no possibility to continue their feeding. But in the 4th instar larvae, because of slow effects of Bt, their feeding on leaves in some treatments continued for up to 100 percent. Thus, application of Dipel and high dosage BtH against 2nd instar larvae of the pest will be more effective than other treatments in Arasbaran forests.

In this research the GYPSY flora of Robat - Sefid, Khorasan province, Iran has been studied. Altogether, 271 herbarium were collected. They are including in 23 families, 66 genera and 85 species. Density and coverage of different species in 100 random sample plots were counted and measured. Respectively 28 soil samples were analyzed. Depending to the amount of gypsum in the soil and occurance of the plants on different contents of gypsum, 3 categories were recognized for plants, i.e. obligatory (2 species), preferential (19 species) and non differential (64 species). Onobrychis amoena ssp. meshhedensis anc Lomatopodium staurophyllum are obligatory species. Chorotype of the species were determined as follows:Irano - Turanian = %75.3Irano - Turanian & Sahara - Sindian = %8.2Irano - Turanian & Meditteranian = %3.5Irano - Turanian & Europa - Sieberian = %2.4Polyregion = %8.4Hemicryptophyte = %52.9, Therophyte = %23.5, Chamephyte = % 15.3, Therophyte / Hemicryptophyte = %3.5, Hemicryptophyte / Chamephyte = %1.2, Phanerophyte / Chamephyte= %2.4.

In this work, the GYPSY flora in the west of Semnan province was studied in 32 stations using transects and unique plots. The major factors studied were the presence and relative coverage of the plants, characteristics of gypsifrous soils, the rate of gypsophily potentials of plants and percentage of gypsum contents in their soil samples. Based on these results, the plants were classified into three groups: obligatory GYPSY flora (eight species), preferential GYPSY flora (28 species) and nondifferential kinds (70 species). In this area, of 106 species determined, two species were gymnosperms, 11 monocotyledons and the rest belonged to the dicotyledons. All obligatory species were native to Iran, and six species were endemic to the Semnan province.