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Eleven species of Chalcidoidea (Hymenoptera) belonging to Aphelinidae, Encyrtidae, Eriaporidae and Signiphoridae associated with the cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) were collected and identified during 2017-2018 from Khuzestan province in the southwestern Iran. Prochiloneurus rex (Girault) (Encyrtidae) is new record for the fauna of Iran. Meanwhile, biological associations of Bothriothorax serratellus (Dalman), Leptomastix dactylopii Howard and L. mayri Özdikmen (Encyrtidae) as parasitoids and Marietta picta (André), P. rex and Chartocerus kurdjumovi (Nikolskaya) (Signiphoridae) as hyperparasitoids of Ph. solenopsis were new.
 

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 The date palm dust mite Oligonychus afrasiaticus (McGregor) is one of the most important pests of the date palms Phoenix dactylifera L. around the world. This pest causes reduction in the economic value of the product, and sometimes its damage reaches up to 100% in the southern provinces of Iran. The population fluctuations and spatial distribution of this pest on two more common varieties (Sayer and Barhi) were investigated in Ramshir City, Khuzestan Province, southwestern Iran. For this purpose, two date palm plantations of 2 ha that had those two varieties of date palm trees were selected, and 10 trees of each variety in each orchard were selected randomly. Sampling was done from North, South, East, and West of each date palm every four days from mid-May to early November, during 2020 and 2021. The results showed that the spider mite appeared on the clusters of two varieties from the beginning of June, and the peak population of mites on both varieties was recorded in September, in both years. Significant difference was observed between different sampling times during those two years and the two varieties: Sayer (F₁._{916, 9.580}= 183. 695, P< 0.0001) and (F_{2.344, 11.720}= 58. 104, P< 0.0001) and Barhi (F_{1.541, 4.622}= 89.010, P< 0.0001) and (F_{1.688, 5.065}= 31. 137, P