Stem galls affect oak foliage with potential consequences for herbivory

Abstract

Abstract. 1. On two dates, foliar characteristics of pin oak, Quercus palustris, infested with stem galls caused by the horned oak gall, Callirhytis cornigera, were investigated, and the consequences for subsequent herbivory assessed. 2. Second‐instar caterpillars of the gypsy moth, Lymantria dispar, preferred foliage from ungalled trees. 3. Ungalled trees broke bud earlier than their galled counterparts. 4. Galled trees produced denser leaves with higher nitrogen and tannin concentrations, but foliar carbohydrates did not differ among galled and ungalled trees. 5. Concentrations of foliar carbohydrates in both galled and ungalled trees increased uniformly between the two assay dates. Nitrogen concentrations were greater in leaves from galled trees, and decreased uniformly in galled and ungalled trees over time. Foliar tannins were also greater in foliage from galled trees early in the season; however, foliar tannins declined seasonally in galled tissue so that by the second assay date there was no difference in tannin concentrations between galled and ungalled foliage. 6. In spite of differences in foliar characteristics, performance of older, fourth instar gypsy moth caterpillars did not differ between galled and ungalled trees.

Arthropod-induced neoplastic formations on trees change photosynthetic pigment levels and oxidative enzyme activities

“…Another important question concerns potential biochemical changes in host plants due to neoplastic formation. Only limited evidence so far support the existence of these changes (Foss & Rieske 2004). The present study for the first time showed the effect of neoplastic growth on host plant defense reactions in different gall-former Á/host plant combinations.…”

“…While there is a limited amount of information on biochemical differences in plant vs gall tissues, several reports are available concerning the effect of gall-forming herbivore on photosynthesis and biochemical characteristics of non-gall tissues of host plants (Larson 1998;Foss & Rieske 2004). So far, no information is available on changes in host plant adaptive responses including defense reactions due to gall induction by a gall-former.…”

Differential responses in American (Castanea dentata Marshall) and Chinese (C. mollissima Blume) chestnut (Falales: Fagaceae) to foliar application of jasmonic acid

“…The top leaf from each seedling was excised, weighed, and placed individually in florists water picks in 217 cm clear rearing boxes. Newly molted fourth instar gypsy moth larvae (Otis Air Force Base, MA, USA) (USDA-PPQ permit number 73568) previously reared on wheat-germ based artificial diet were starved for 24 h, weighed, and added individually to each assay box (N = 19 AM-JA and AM-C, N = 10 CH-JA and CH-C) (Foss and Rieske, 2004;Kellogg et al, 2005). Assays were kept in growth chambers (Percival Scientific, Perry, IA) (23 8C; 15 : 9 L : D photoperiod) and monitored at 4 hr intervals during daylight hours.…”

Gall (Trioza rusellae Tuthill) insect identification in Brosimum alicastrum Swartz leaves in Yucatán, Mexico

“…No obstante, el árbol de B. alicastrum presenta diversos problemas; entre ellos, el más importante es el ataque de plagas como el del psílido Trioza rusellae Tuthill, que llega a producir 400 a 600 agallas por hoja, afectando la fotosíntesis (Piotto, 2007). Las agallas son estructuras anormales de tejidos que se desarrollan por una reacción específica a la actividad de un organismo inductor (Allison & Shultz, 2005;Foss & Rieske, 2004;Price, 2005).…”

“…However, B. alicastrum tree has several problems; among them, the attack of pests such as the psyllid Trioza rusellae Tuthill is the most important, which produces 400-600 galls per leaf, affecting photosynthesis (Piotto, 2007). Galls are abnormal tissue structures that are developed due to a specific reaction to the activity of an inductor body (Allison & Shultz, 2005;Foss & Rieske, 2004;Price, 2005).…”