Myzus cerasi
(black cherry aphid)

M. cerasi occurs throughout Europe, the Middle East, and across Asia, from India and Pakistan to Siberia and the far eastern part of the Palearctic. It has been introduced more recently into Australia, New Zealand and North America (Blackman and Eastop, 1994).

Primary host plants are Prunus cerasus (Morello cherry) and Prunus avium (sweet cherry), and sometimes other Prunus species (Rosaceae). Secondary hosts occur in the Rubiaceae (Galium spp.), Scrophulariaceae (Veronica spp.) and Cruciferae (Capsella spp.), and occasionally Caprifoliaceae and Compositae. Different secondary hosts are utilized in different geographical regions, for example, cruciferous hosts are important in the USA (Gilmore, 1960; Blackman and Eastop, 1984).

M. cerasi has a heteroecious holocyclic life-cycle. It alternates between primary hosts of Prunus and secondary hosts mainly in the Rubiaceae, Scrophulariaeceae and Cruciferae.

Eggs overwinter on primary hosts. In Lithuania, overwintering eggs hatched, to produce fundatrices (stem mothers), when the thermal constant was 43-60.9 day-degrees C, above a threshold of 3°C, while up to 12 generations occurred on cherry in one season (Rakauskas, 1984). In Oregon, USA, the fundatrices first appeared in mid to late March, when the cherry buds were swelling. By late March, when buds were at the green tip stage, all the eggs have hatched. The fundatrices began reproducing by mid-April, when the trees were in full bloom. One week later the first leaf curling injury is usually found. The apterous virginoparae, the progeny of the fundatrice generation, began reproducing in early May (Gilmore, 1960). Aphids form dense black colonies at shoot tips of cherry in the spring, causing leaf curling which can result in severe economic damage.

M. cerasi can in some cases continue throughout the year on cherry, in which case it is of considerable economic importance. In Oregon, USA, for example, Gilmore (1960) reported that cherry trees sprayed with insecticide became re-infested in late spring and summer, via winged migrants, with some apterous virginoparae remaining on the primary hosts until autumn; although these could only survive on water sprouts and other succulent tree parts. Winged gynoparae migrated between cherry trees in the autumn, producing oviparae (sexual females) on the primary host, but males were not produced from populations of cherry - they all migrated from secondary hosts. A partial or complete migration to secondary hosts in late spring is the more usual life-cycle of M. cerasi. A series of generations occur on secondary hosts during the summer, commonly Galium spp. or Veronica spp. in Europe and cruciferous species in the USA, before shortening day-length induces the formation of the gynoparae, and then the males, which migrate back to cherry. In Oregon, oviparae are found on cherry from September and males return to cherry in early November. Each oviparae lays on average 4.5 eggs in bark crevices (Gilmore, 1960).

Ants commonly attend aphid colonies on cherry. Lasius niger and Myrmica laevinoides were the commonest species found with M. cerasi in a German study (Gruppe, 1990). Aphids may thrive best on larger trees, which provide greater shade from direct sunlight (Gilmore, 1960).

Natural enemies of M. cerasi in Lithuania were described by Rakauskas (1984) and parasitoids of the Mediterranean region were described by Ferrari and Burgio (1994).

In Oregon, USA, large numbers of natural enemies were present in cherry orchards by late May, although this was too late to prevent economic damage. Coccinellids were the most important group of predators, followed by syrphids, and then chrysopids. Of 3600 aphids collected from cherry in June, about 17% were parasitized by braconid parasitoids (Gilmore, 1960).

Colonies can be found via inspection of curled young growing shoots of cherry trees in the spring. Winged M. cerasi in cherry orchards later in the spring and early summer can be detected using yellow sticky traps.

M. cerasi is a complex of subspecies, or possibly species, with different life cycles and secondary host plants (Dahl, 1968). Three morphologically identical subspecies occur in Central Europe (Gruppe, 1988a). M. cerasi sensu stricto thrives on Prunus cerasus and P. avium, while M. cerasi pruniavium generally infests only P. avium. Both of these subspecies have worldwide distributions and migrate to secondary hosts, particularly Galium spp. and Veronica spp. in Europe. However, electrophoretic studies have shown differences in esterases of these two subspecies (Gruppe, 1988a). Gruppe (1988b) suggested that M. cerasi sensu stricto and M. cerasi pruniavium are subspecies that may be on the way to developing into different species. Indeed, Börner first considered them as distinct species, when he split off Myzus pruniavium from Myzus cerasi (Müller, 1986). The other subspecies in Central Europe is M. cerasi veronica, which is not found elsewhere in the world and lives exclusively on secondary host plants of Veronica spp. (Ossiannilsson, 1959; Gruppe, 1988b).

A further subspecies, Myzus cerasi umefoliae Shinji, 1941, occurs only in Japan and lives on Prunus mume and not cherry, migrating to Artemisia capillaris in the spring (Takahashi, 1965). Blackman and Eastop (1994) have suggested, however, that this aphid is probably not a subspecies of M. cerasi, but another species, Myzus prunisuctus.

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Chemical Control

For control of M. cerasi, compounds with a predominantly contact or systemic effect, such as dimethoate and pirimicarb have been recommended. These are applied only in infested areas, and the timing of spray applications should be based on local monitoring (Vasev, 1983).

Biological and Cultural Control

The banding of tree bases with glue prevents the ants that attend M. cerasi from climbing up the trees. These ants act to deter natural enemies, which are more prevalent in banded trees than unbanded trees (Fontanari et al., 1993). The application of glue to tree bases can be as effective in controlling M. cerasi as spraying with pirimicarb (Perez et al., 1995).

Host-Plant Resistance

Gruppe (1991) described resistance in cherry trees to M. cerasi for hybrids between and within the sections Pseudocerasus and Eucerasus. Species and hybrids of the section Pseudocerasus were rarely colonized by aphids. Within the section Eucerasus, Prunus fruticosa, and hybrids of Prunus avium x Prunus cerasus, were relatively resistant.