Page 4 - Volume 6, Issue 1, January 2013

Kapaxidi

2

Eriophyoid mites (Acari: Eriophyoidea)

have been recognized as important pests

in agriculture and forestry all over the world

(Lindquist

et al.

, 1996). A number of erio-

phyoid species are considered to be main

pests on some crops, while others are

known to be a quarantine threat for several

countries. Nevertheless, several eriophyoid

species seldom attain high population lev-

els and thus their economic importance is a

matter of discussion (Duso

et al.

, 2010).

There are quite a few difficulties evalu-

ating eriophyoid population densities and

related yield losses in most cases of erio-

phyoid infestations. Their minute size and

concealed way of life (several species live

and reproduce well hidden in buds or in in-

duced plant structures, like galls, erinea and

blisters) represent an obstacle for detailed

studies aiming at determining their impact

on agricultural crops. The small size and the

behavior of eriophyoids are frequently im-

plied in misdiagnoses with implications for

yield losses (Duso

et al.

, 2010). In contrast,

their symptoms are sometimes spectacular

but not of economic impact. Knowledge of

the economic impact of eriophyoids on crop

yields and threshold levels is a fundamental

requirement for the improvement of IPM.

Up to date approximately 100 species of

eriophyoid mites have been reported from

Greece (Malandraki, 2012), thirty three of

them in agricultural orchards and grape-

vines. In Table 1, the name of the mite spe-

cies and the host plant species as well as the

corresponding references are summarised.

Most of the papers are dealing with the tax-

onomic status, distribution records and con-

trol. A few studies deal with their biology

and control.

Eriophyoid species in Greek orchards

Eriophyoids of stone fruits

Acalitus phloeocoptes (Nalepa) [Phy-

toptus phloeocoptes Nalepa, Eriophyes

phloeocoptes (Nalepa)]

Common name: plum blister mite

Damage: The plum blister mite infests main-

ly almond and plum. On almond, it causes

permanent irregular galls of various sizes

around the buds and deforms the fruit. In-

fested trees fail to form fruit buds and lose

vigor. On plum, the mites form small, irregu-

lar, subsphaerical galls, 1.3-1.8 mm in diam-

eter surrounding the buds and also deform-

ing the fruit. The galls may appear singly

or clustered around the buds and become

woody.

On almond the damage appears to be

progressive and irreversible resulting in

death of the tree in 3-6 years. Unlike almond,

infested plum trees often recover from mite

attack and do not show permanent injury

(Keifer

et al.

, 1982).

In the area of Magnesia (Central Greece)

on “Skopelos” plum tree the mite starts to

migrate from the galls to new buds in mid-

April and the migration phase lasts 50 days.

Population builts up until December with

successive generations, not damaging the

production or the tree (Papanikolaou and

Bakoyiannis, 1991).

Aculus fockeui (Nalepa and Trouessart)

[Phyllocoptes fockeui Nalepa and Troues-

sart, Vasates fockeui (Nalepa and Troues-

sart)]

Syn:

Phyllocoptes cornutus

Banks [

Aculus cor-

nutus

(Banks);

Vasates cornutus

(Banks)]

Phyllocoptes paracornutus

Keifer

Common name: plum rust mite

Damage: This is a pest mainly of plums,

peaches/nectarines and cherries in orchards

and nurseries. This mite produces asteroid

chlorotic spots on leaves. When populations

are high the leaf is wavy or slightly twisted

about its longitudinal axis. Heavy infesta-

tions of

A. fockeui

may form rosette shoots

and keep leaves from expanding to nor-

mal size. Deutogynes hibernate in niches or

near the current season growth. They crawl

into bark crevices, especially around inju-

ries, but are also behind potentially active

buds, or under available loose bud scales.

As the buds expand in spring the deutog-

ynes crawl to, and feed upon, emerging em-

bryonic leaves and lay eggs. Trees are losing