Brevipalpus is a large, widespread genus, including over 65 species of very small flat mites. They are divided into six groups according to the number of lateral setae in the posterior half of the body (hysterosoma), the number of sensory setae on tarsus II of the female and the number of terminal setae on the palpus (Baker and Tuttle, 1987).
The Chilean grape flat mite is included in the obovatus group, having six pairs of lateral hysterosomal setae (Baker and Tuttle, 1987) and one sensory cylindrical seta (solenidion) on tarsus II.
Female
Body oval, 320-340 µm, body setae very short, dorsal setae 14 to 16 µm. Six pairs of short dorsolateral setae, of which five pairs are strictly hysterosomal and the sixth pair is humeral (Jeppson et al., 1975). The distal segment of the palpus has three setae and tarsus II has a single distal solenidion rod.
The main distinguishing character is the propodosoma, which is evenly reticulate. The latter character separates B. chilensis from Brevipalpus obovatus;this feature can be better seen under a phase contrast microscope.
Male
The male is very similar to the female with respect to the above morphological features.
Protonymph
From laboratory pure cultures, it is confirmed that the main characters used in separation are the shapes of the first and second propodosomal setae and the final three hysterosomal pairs, which are oblong in shape, whereas all other dorsal setae are much shorter and setiform.
Deutonymph
The dorsocentral setae are short and setiform;all others are oblong of denticulated margin.
Under field conditions, all Brevipalpus mites look very similar in colour, shape and size. They can be easily found in preferred host plants with the aid of a x15 magnification hand lens. Overwintering adult females should be searched for on the underside of leaves, the pedicel disk area of citrus (Citrus spp.) and kiwifruit (Actinidia deliciosa), grape (Vitis vinifera) bunches near the pedicel, and under the bark or petiole cavities in deciduous plants.
A diagnostic Lucid key to 19 species of Brevipalpus is available in Flat Mites of the World.
For quarantine inspection purposes, the grape bunches can be washed with detergents within a funnel system to convey the water down and inspect specimens in a collecting pan.
Related invasive species
- Brevipalpus chilensis
Related Farm Practice
- Groups
This species is commonly found throughout central Chile on a variety of cultivated hosts such as grapes (Vitis vinifera), lemons (Citrus limon), kiwifruits (Actinidia deliciosa), persimmons (Diospyros kaki), and various flowers and ornamentals. In terms of abundance, Ligustrum spp. (privet) is by far the most important host plant;another character that links B. chilensis with Brevipalpus obovatus (see 'Similarities to other species').
The oldest known mounted specimens kept at the University of Chile Agricultural Museum, Chile, were collected on wine grapes (V. vinifera) in Central Chile in 1909. All specimens were labeled 'Tetranychid mites'. In terms of economic damage and because of its quarantine connotation, table grapes, Citrus spp., chirimoya (Annona cherimola), banyan (Ficus indica [Ficus benghalensis]), kiwifruit (Actinidia deliciosa) and a few others are extremely important because several markets, namely USA and Mexico, require a zero tolerance fumigation. However, in terms of physiological damage to the host, the wine grape is still the most recurrent.
Small, limited mite populations can be found on carnations (Dianthus caryophyllus), Euonymus, snapdragon (Antirrhinum spp.), chrysanthemum (Chrysanthemum spp.), Vinca sp., Ampelopsis sp., and assorted broad-leaf plants, including pome fruits. Under laboratory or greenhouse conditions, potted beans and privet (Ligustrum) may yield high mite populations.