Skip to main content

Soft scale insect, repens scale (Pulvinaria rhododendri), on Rhododendron spp. in Northern Europe

Soft scale insect, repens scale (Pulvinaria rhododendri), on Rhododendron spp. in Northern Europe

NEWS - Repens scale (Pulvinaria rhododendri Kahrer & Hodgson, Hemiptera: Coccomorpha: Coccidae) was discovered in Rhododendron spp. (Ericaceae) in Denmark and Norway which appears taxonomically close to P. camelicola Signoret and P. floccifera Westwood with an uncertain geographic origin, but is likely to have been introduced to northern Europe via imported live plants.

P. rhododendri is distinguished from P. floccifera, P. camelicola and all other Pulvinaria species by a combination of characters-a medial band of large conical spinous setae extending from the anal plate anterior to the head and simple pores with strongly sclerotic margins present in a narrow medial band between the large conical spinous setae.

The new species also differs from P. floccifera by the presence of a type III tubular canal submarginally between the lateral stigmatic clefts (vs. absent). The species is named after the genus of the host plant from which it is most commonly collected, Rhododendron L. P. rhododendri is also found on Vaccinium myrtillus L. (Ericaceae) but only when Rhododendron spp. are present nearby.

In Denmark, the species has been found in gardens on the mainland at Hadsund Syd, Jutland, and at Tyfelse on the island of Zealand, 25 km southwest of Copenhagen. These gardens are probably about 150 km apart. In Norway, P. rhododendri has been collected from Arendal and Grimstad on the south coast, about 250 km north of Jutland, Denmark.

The new species is only known from a small area in northern Europe and was probably first found on Rhododendron spp. in Norway in 2018 causing severe sooty mold infestations. This plant was eradicated but the population appears to have persisted as specimens were collected at the same location in 2022.

It is likely that the first discovery also referred to P. rhododendri and since it is still present, it is clearly growing and overwintering under northern European conditions, having survived two winters in between.

To date, no geographical surveys have been carried out to determine the distribution of the species. This host plant could spread more widely as it is cultivated, is a popular plant and is often moved in the plant trade.

The new species is potentially important as a pest of urban plants, especially Rhododendron spp., based on the distribution mentioned above. In the field, P. rhododendri is somewhat similar to P. camelicola which may have been mistaken for non-entomologists in the past.

P. rhododendri, like other Pulvinaria species, produces abundant honeydew, so the growth of sooty mold is a major problem, forming a thick, unsightly layer covering the leaves. However, so far it does not appear to cause host mortality or other problems.

Original research

Andreas Kahrer & Chris J. Hodgson (2024). A new species of the soft scale insect genus Pulvinaria Targioni Tozzetti (Hemiptera: Coccomorpha: Coccidae) on Rhododendron spp. in Northern Europe. Zootaxa 5512 (2): 233-239, DOI:10.11646/zootaxa.5512.2.7

Dlium theDlium

Popular Posts

Humpback whales (Megaptera novaeangliae) manufacture bubble-nets as tools to increase prey intake

NEWS - Humpback whales ( Megaptera novaeangliae ) create bubble net tools while foraging, consisting of internal tangential rings, and actively control the number of rings, their size, depth and horizontal spacing between the surrounding bubbles. These structural elements of the net increase prey intake sevenfold. Researchers have known that humpback whales create “bubble nets” for hunting, but the new report shows that the animals also manipulate them in a variety of ways to maximize catches. The behavior places humpbacks among the rare animals that make and use their own tools. “Many animals use tools to help them find food, but very few actually make or modify these tools themselves,” said Lars Bejder, director of the Marine Mammal Research Program (MMRP), University of Hawaii at Manoa. “Humpback whales in southeast Alaska create elaborate bubble nets to catch krill. They skillfully blow bubbles in patterns that form a web with internal rings. They actively control details such ...

Asian palmyra palm (Borassus flabellifer)

Asian palmyra palm ( Borassus flabellifer ) is a species of Arecaceae , palm, sturdy, single-stemmed, cylindrical shape, growing 15-30 meters tall and with a trunk diameter of about 60 cm. The leaves are clustered at the tip of the trunk, forming a rounded crown . The leaf blade resembles a round fan , up to 1.5 meters in diameter. The leaflets are 5-7 cm wide, and the underside is whitish with a waxy coating. The leaf stalk is up to 1 meter long, with a broad, black midrib at the top and a row of two-pointed spines . The inflorescence is borne on a cob, 20-30 cm long, and the stalk is about 50 cm long. The fruits are clustered in clusters of about 20, round, 7-20 cm in diameter, with a brownish-black outer skin and yellow flesh on the inside. The fruit has three seeds in a thick, hard shell. Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Liliopsida Order: Arecales Family: Arecaceae Subfamily: Coryphoideae Tribe: Borasseae Subtribe: Lataniinae Genu...

Javan mocca or Javan slender caesar (Amanita javanica)

OPINION - Javan mocca or Javan slender caesar ( Amanita javanica ) is a mysterious fungus species and has been enigmatic since it was first reported by Boedijn in 1951 and after that no explanation or reporting of specimens is believed to be the same as expected. Boedijn (1951) described A. javanica which grew on Java island as having the characteristics covered in the Amanita genus. Corner and Bas in 1962 tried to describe Javan mocca and all species in Amanita based on specimens in Singapore. Over time some reports say that they have found A. javanica specimens in other Southeast Asia including also China, Japan, India and Nepal. But there is no definitive knowledge and many doubt whether the specimen is the same as described by Boedijn (1951). I was fortunate to have seen this species one afternoon and soon I took out a camera for some shots. In fact, I've only met this mushroom species once. Javan mocca is an endangered species and I have never seen in my experience in...