THE LIFE HISTORY, FOLIAGE DAMAGE, AND CONTROL OF THE BALSAM TWIG APHID, MINDARUS ABIETINUS (HOMOPTERA: APHIDIDAE), IN FRASER FIR CHRISTMAS TREE PLANTATIONS OF WESTERN NORTH CAROLINA,

Abstract

Mindarus abietinus Koch causes leaf-curl and shoot-stunting of the new foliage of Fraser fir in North Carolina. Although this injury usually has a minimal impact on the trees' health and vigor, the injury can reduce the aesthetic quality and hence the marketability of Christmas trees. The overwintering egg gives rise to the fundatrix in late March. In May and June the fundatriginia and sexuparae appear. In June the sexuales are produced and by late June oviposition has occurred. The egg remains dormant until the following spring. The within-crown distribution of the various life stages is presented. Most of the injury can be minimized by maintaining vigorous growth, and timing necessary insecticide applications. Under most circumstances chemical control should only be considered during the last year or two before harvest. Dimethoate, pirimicarb, acephate, or chlorpyrifos will provide adequate control after egg hatch but before bud break.

Temperature-manipulated dynamics and phenology ofMindarus abietinus(Hemiptera: Aphididae) in commercial Christmas tree plantations in Québec, Canada

“…However, spring emergence of stem mothers and the appearance of overwintering eggs were observed between three and nine days later than in the mid-1990s. This slight yet consistent difference in phenology could partly be explained by regional differences in temperature, as the experimental sites selected by Deland et al (1998) were located~80 km south of the ones used in this study, in a slightly warmer climate implying possibly faster development for the stem mother and her colony, which is also the case for M. abietinus populations studied in lower latitudes like North Carolina, United States of America (Nettleton and Hain 1982) and southern Michigan, United States of America (Fondren and McCullough 2003).…”

“…Hence, the continuous feeding of a colony on the sap of the host tree can damage the host tree at high aphid densities. The deformation of the shoot and its needles usually forms a protective pseudogall around the growing aphid colony, which reduces the aesthetic value of Christmas trees, and causes economic losses for growers (Nettleton and Hain 1982;Bradbury and Osgood 1986;Kleintjes et al 1999).…”

Seasonal natural history of aphidophagous Syrphidae (Diptera) attacking the balsam twig aphid in balsam fir (Pinaceae) Christmas tree plantations

“…In the early season when no aphid damage was yet visible on current-year shoots, sample shoots were collected at random. Current-year shoots were selected, because balsam twig aphid colonies develop exclusively on these shoots (Nettleton and Hain 1982). Each sample of current-year shoots was kept in a plastic bag inside a cooler until examination under a stereomicroscope in the laboratory.…”

“…Their progeny grow rapidly and form colonies that feed on current-year shoots during the elongation period. Their feeding on the current-year shoots results in needle distortion and stunting of shoots (Varty 1966; Saunders 1969; Nettleton and Hain 1982; Bradbury and Osgood 1986). Such damage is usually of little concern in natural forests but in Christmas tree plantations, it reduces the aesthetic value of balsam fir trees and can have substantial economic impact (Berthiaume 1998; Deland et al .…”

“…However, syrphid flies attacking the balsam twig aphid during larval development are not as well known. In North Carolina, United States of America, Nettleton and Hain (1982) identified two species of Syrphidae ( Allograpta obliqua (Say) and Syrphus rectus Osten Sacken) attacking the balsam twig aphid in Christmas tree plantations of Fraser fir, Abies fraseri (Pursh) Poiret (Pinaceae), but they did not study their life history. Kleintjes (1997) collected 10 species of syrphid flies near balsam twig aphid colonies but they were not linked to larval predation on the aphid.…”