Latitudinal variation in soil biota: testing the biotic interaction hypothesis with an invasive plant and a native congener.

Soil biota community structure can change with latitude, but the effects of changes on native plants, invasive plants, and their herbivores remain unclear. Here, we examined latitudinal variation in the soil biota community associated with the invasive plant Alternanthera philoxeroides and its native congener A. sessilis, and the effects of soil biota community variation on these plants and the beetle Agasicles hygrophila. We characterized the soil bacterial and fungal communities and root-knot nematodes of plant rhizospheres collected from 22 °N to 36.6 °N in China. Soil biota community structure changed with latitude as a function of climate and soil properties. Root-knot nematode abundance and potential soil fungal pathogen diversity (classified with FUNGuild) decreased with latitude, apparently due to higher soil pH and lower temperatures. A greenhouse experiment and lab bioassay showed native plant mass, seed production, and mass of beetles fed native foliage increased with soil collection latitude. However, there were no latitudinal patterns for the invasive plant. These results suggest that invasive and native plants and, consequently, their herbivores have different responses to latitudinal changes in soil-borne enemies, potentially creating spatial variation in enemy release or biotic resistance. This highlights the importance of linking above- and below-ground multitrophic interactions to explore the role of soil biota in non-native plant invasions with a biogeographic approach.

Description of a nomen nudum species of Liriomyza Mik and the first record of Liriomyza blechi Spencer from Brazil (Insecta: Diptera: Agromyzidae).

The nomen nudum Liriomyza flagellae is formerly described in this paper as Liriomyza valladaresae sp. nov., based on male and female specimens collected in the Brazilian Amazon and reared from leaves of Alternanthera tenella and Amaranthus viridis (Amaranthaceae). Information on the puparium and the biology of this new species are provided. The species Liriomyza blechi, previously recorded from the U.S.A., Guadeloupe and Dominican Republic, is newly recorded from Brazil, reared from leaves of Blechum pyramidatum (Acanthaceae) and Spigelia anthelmia (Loganiaceae).

Rhodochlanis suaedicola sp. nov. (Hemiptera: Sternorrhyncha: Psylloidea: Aphalaridae) associated with Suaeda japonica (Amaranthaceae) from Korea.

A new psyllid species, Rhodochlanis suaedicola sp. nov., is described and illustrated from Korea based on adults and fifth instar immatures. Rhodochlanis is reported for the first time from Korea. The new species is associated with Suaeda japonica (Amaranthaceae) growing in saline habitats. Salt marshes in Korea are threatened by sea side developments. It is suggested that these habitats should be protected to ensure the survival of R. suaedicola.

Natural infection of Alternanthera tenella (Amaranthaceae) by a new potyvirus.

A virus was isolated from joyweed (Alternanthera tenella Colla-Amaranthaceae), a common weed in tropical and sub-tropical regions. Examination by electron microscopy showed long flexuous particles with an average length of 756 nm in crude sap. Serological results showed positive reaction with antisera to PVY-O. A fragment of 1772 nucleotides was sequenced. The CP sequence shares 76% of identity with the CP of Potato virus Y strain NTN. These results confirm that the virus is a new potyvirus infecting A. tenella, and the name Alternanthera mild mosaic virus (AltMMV) is proposed.

[Occurrence and control of Loxostege stieticatis on host plant Haloxylon ammodendron to Cistanche deserticola].

The investigation of the occurrence and pesticide experiments of Loxostege stieticatis on Haloxylon ammodendron showed that Loxostege stieticatis is an explosive pest; it can be controlled with lower toxic pesticides such as deltametrin; the innocuous comprehension measure should be a good choice to control in field.