Pests

Spider mite on Hydrangea macrophylla

Hydrangea macrophylla (Thunb.) Ser.

A pest of Hydrangea macrophylla that damages the plant by sucking cell sap from the leaf mesophyll, leading to chlorosis, loss of turgor, and premature leaf drop.

In the reference 10 varieties crop Bigleaf hydrangea, where this is mentioned in the description.

The primary species affecting Hydrangea macrophylla are the two-spotted spider mite, Tetranychus urticae, characterized by its wide polyphagy, and the Kanzawa spider mite, Tetranychus kanzawai, which is often identified as a specialized hydrangea mite.

Damage symptoms appear as small light-colored dots on the leaves, which merge into large discolored spots as the colony develops. The pests are localized mainly on the underside of the leaf blade, where, in cases of high infestation, they form a fine web accompanied by leaf deformation and desiccation.

Data on the existence of specific resistance genes in Hydrangea macrophylla to these pests are absent in modern breeding literature, as the breeding priorities for this crop are more often directed toward controlling fungal diseases, such as powdery mildew.

General information about the subject — on the page Spider mite.

Sources8

Varieties of Bigleaf hydrangea mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.