Family common name: common sawflies
Genus: Hoplocampa Hartig, 1837
The Tenthredinidae are the most species-rich family and are found throughout the world, in all continents but Antarctica. They are known as the “common sawflies.” They can generally be recognized by a cylindrical body and long, segmented antennae. Otherwise, they come in a variety of colors, sizes, and forms (Goulet 1992).
Nematinae is the second-largest subfamily of Tenthredinidae with over 1,250 species (Prous et al. 2014). They are most diverse in northern Eurasia and North America; only a few species occur in the Southern Hemisphere. Nematinae sawflies have a variety of feeding habits including external leaf feeding, leaf mining, and gall forming, and feed on a variety of hosts (Smith 2003b).
The Nematinae have been subject to numerous revisions in recent years. As of 2021, there are no comprehensive keys to many of the North American species of Nematinae (Prous et al. 2014). Because of changing taxonomy and extreme variability in morphology, identifying genera and species in the Nematinae may be more challenging than in other subfamilies of Tenthredindae. For this reason, knowing the host or behaviors of a specimen can be extremely helpful for identification within this subfamily.
Hoplocampa are about 7–9 mm in length, with variable colors. They feed on developing fruits of Rosaceae, including several agricultural crops such as apple, cherry, and pear, making them an economic pest (Ross 1943c).
There are 45 described species worldwide. Twenty-two species occur in North America (Taeger et al. 2018).
A key to North American species is included in Ross 1943c.
Hoplocampa may be confused with other genera in the subfamily Nematinae, particularly those with shorter antennae such as Adelomos or Caulocampus, but can be distinguished from most other genera by the wide space between fore wing veins M and Rs+M on vein R, the presence of 2r-rs, the length of the scape and pedicel, and the location of fore wing vein 2m-cu (Goulet 1992).
Two sawflies are pests of plum in Europe. Hoplocampa minuta, the black plum sawfly, is a more significant economic pest than H. flava, the yellow plum sawfly, in most regions, appearing in greater abundance and inflicting greater damage. Both are multivoltine (Tamošiūnas et al. 2014, Liston et al. 2019a). Because of the habit of feeding inside of the fruit, control methods are difficult to implement (Caruso and Cera 2004).
Hoplocampa brevis is a pest of pear in southern regions of Europe, and occasionally feeds on apple as well (Liston et al. 2019a).
Hoplocampa cookei, a native species also known as the cherry fruit sawfly, has been recorded as a pest of cherry in California (Ross 1943c).
The introduced H. testudinea, known as the apple sawfly, is a pest of apple fruit in Europe and North America (Liston et al. 2019a). Though the species is univoltine, the fact that one larva can damage up to five or six apple fruits in its lifetime results in significant annual damage to fruit yields. Because of the protection the fruit provides, control methods for this pest are challenging (Pyenson 1943).
In North America, Hoplocampa feeds on Malus (apple), Crataegus (hawthorn), Pyrus (pear), Prunus (cherry, plum), and Amelanchier (serviceberry) (Ross 1943c).
Females oviposit into the calyx of a flower of the host. Larvae bore into and feed on the immature fruit, often visiting several fruits during their development. Affected fruits often cease development and fall off the plant. At maturity, the larvae fall to the ground to overwinter and pupate (Ross 1943c).
World: The genus is known from North America, North Africa, and throughout Europe and Asia (Liston et al. 2019a).
North America: Hoplocampa occurs throughout the United States and Canada (Ross 1943c). Hoplocampa testudinea was introduced from Europe and first discovered on the East Coast in 1939 in New York (Pyenson 1943), and on the West Coast in 1940 in British Columbia (Downes and Andison 1942). It has since become established in the northeastern United States and southeastern Canada (GBIF).
Map data from: GBIF.org (29 October 2019) GBIF Occurrence Download Hoplocampa
Details about data used for maps can be found here.