Twig Girdler Research Articles

Alguns aspectos da biologia do serrador, <i>Oncideres dejeani </i>Thompson, 1868 (Coleoptera: Cerambycidae).

Realizou-se este trabalho objetivando determinar alguns parâmetros comparativos da biologia do serrador, Oncideres dejeani Thomson,1868 (Coleoptera: Cerambycidae) sobre aroeira preta, Lithraea brasiliensis L. March (Anacardiaceae) e pau de leite, Sebastiania brasiliensis Spreng. (Euphorbiaceae), em São Sepé - RS, durante o período 1989-1990. Mediu-se o comprimento e a largura do orifício de emergência dos adultos do serrador e, o comprimento e volume da galeria larval-pupal. O orifício de emergência do adulto de O. dejeani apresenta formato ovalado em pau de leite e quase circular em aroeira preta. A larva se desenvolve em galhos de vários diâmetros, independente da espécie de planta hospedeira, consome igual volume de madeira e constroi galeria de comprimento similar nas duas espécies botânicas estudadas.

The effects of twig girdlers (Cerambycidae) and node borers (Bostrichidae) on primary production in mesquite (Prosopis glandulosa)

Production of leaves and shoots on branches of mesquite shrubs which had been girdled by the mesquite twig girdler (Oncideres rhodisticta) was compared with the production of unaffected branches on girdled and ungirdled shrubs. We made similar comparisons on mesquite which had been subjected to simulated girdling or terminal node destruction of 40–80 per cent of the branches. There was no significant difference in shoot and leaf growth in either natural or simulated damaged plants compared to controls. These studies suggest that the timing of the activity of stem-destroying insects may be important in minimizing damage to the plant.

Biology and Ecology of a Mesquite Twig Girdler, Oncideres rhodosticta,1 in West Texas2

Oncideres rhodosticta Bates (Coleoptera: Cerambycidae) causes severe pruning of small branches of mesquite, Prosopis glandulosa Torr., in many areas of Texas. Adults emerge from galleries in girdled branches from late August through November. They feed on tender bark of mesquite around the buds, thorns, and small limbs. Eacli female girdles about one branch and deposits about 8 elliptically ovate eggs beneath the bark of the branch. Within 10–14 days, 98% of the eggs hatch and the larvae feed upon the sapwood, opening the oviposition scar to expel frass after about 3 months. Pupation occurs in late August and early September and is preceded by a prepupal stage. Each larva consumes about 1.44 cc of mesquite wood during its development. Parasites and predators kill 15–22% of the larvae while 34–55% die from undetermined causes. Larvae are attacked by parasites in the families Chalcedectidae, Pteromalidae, Eupelmidae, and Eurytomidae, as well as by predators in the family Cleridae. Twig girdler larvae may compete for space and food with other cerambycids and several species of bostrichids. About 31% of all girdled branches are broken off by wind storms and livestock before adults emerge, resulting in high mortality of the larvae from high temperatures in the branches near the soil surface.

Periploca nigra, a Major Cause of Dieback of Ornamental Juniper in California

Periploca nigra Hodges (Lepidoptera: Walshiidae) is a newly described species which is widely distributed in California. Severe twig dieback of juniper results from the girdling of the stems, beneath the bark, by the larval stage. Because of the nature of the injury, the common name—juniper twig girdler—is proposed for P. nigra . Hosts on which the insect has been collected thus far include: Juniperus chinensis L., J. horizontalis Moench., J. sabina L., and J. virginiana In the San Francisco Bay area in 1963, pupation in the twigs began in late March and reached maximum proportions in early June. Emergence of moths occurred in June and July. Eggs are laid singly on the bark of the twigs, and new larvae were first found in late July. There was no evidence of a second generation. An undescribed braconid ( Microchelonus sp.) exerts a measure of biological control of the larvae.