Relationship Between Susceptibility of Gypsy Moth Larvae (Lepidoptera: Lymantriidae) to a Baculovirus and Host Plant Foliage Constituents

Field efficacy of the nucleopolyhedrovirus of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae): effect of formulations, water pH, volume and time of application, and type of spray nozzle

“…The number of virus-infected and dead larvae (IL) was significantly higher (P<0.05) in plots treated with a virus suspension at pH 6 in relation to plots treated with viral suspensions at pHs 2 and 10, but these had significant more IL than those plots treated only with water (check). These results are similar to those obtained by other authors (Ignoffo & Garcia 1966, Young et al 1977, Keating et al 1988, Batista 1997. The lower efficacy of AgMNPV at pHs 2 e 10 is probably due to the dissolution of the occlusion bodies as a result of an excess of hidrogen (H + ) ions and of oxydril (OH) in acid and basic water, respectively (Ignoffo & Garcia 1966, Batista 1997.…”

“…These may include: solar radiation, particularly the UV spectrum (Jaques 1977, Moscardi et al 1981, Silva 1987; relative humidity and precipitation (Jaques 1967(Jaques , 1977; age and population intensity of the host insect (Boucias et al1980, Moscardi 1983, Silva 1987; pH of the aqueous viral suspension in the spray tank (Young et al 1977, Ignoffo & Garcia 1966, Keating et al 1988, Batista 1997; temperature (Jaques 1977, Johnson et al 1982, Ignoffo 1985; and viral formulation, equipment and application technology (Yearian 1978, Silva 1986). Due to cases of low efficacy, particularly in Rio Grande do Sul, the treated area with the AgMNPV stabilized and even decreased in this state from mid 1990's.…”

Foliar Phenolics are Differently Associated with Epirrita autumnata Growth and Immunocompetence

“…First, the direction of the correlation is the opposite of what would be intuitively anticipated and what has been found in a different system, consisting of oaks and gypsy moth and their viruses (Hunter and Schultz 1993;Keating et al 1988Keating et al , 1990; but see also Lindroth et al 1999). Second, unpublished results have demonstrated a significant increase in hydrolyzable tannins in birch foliage during the peak phase of the E. autumnata cycle.…”

“…Different food-quality-dependent defense mechanisms against predators are common in herbivorous insects: sawflies, for instance, are better at protecting themselves against ants if the food plant contains abundant resin acids (Bjorkman and Larsson 1991), and Chrysomelidae larvae are able to secrete a repellent, which contains compounds obtained from the food plant (Hilker and Schulz 1994). In woody plants, the high levels of foliar hydrolyzable tannins made Lymantria dispar larvae more resistant against their viral diseases (Hunter and Schultz 1993; Keating et al 1988Keating et al , 1990; but see also Lindroth et al 1999). In contrast, phenolic glycoside salicin increased L. dispar larval susceptibility to viral infection (Cook et al 2003).…”

Influence of plant resistance traits in selectiveness and species strength in a tropical plant‐herbivore network

“…Even with this small amount of variation, the combination of foliar trichomes and oxidized phenolics (PC2 defensive index) had synergistic eff ects to increase plant resistance, negatively infl uencing species strength in shrubs and herbivore selectiveness during the dry season in the studied plant-herbivore network. Intermediate concentrations of tannins could be promoted as the result of their simultaneous negative eff ects on herbivores, through a reduced digestibility of plant tissues, and indirect positive eff ects, favoring increased immune responses to diff erent diseases, at least for some herbivore species ( Faeth and Bultman, 1986 ;Keating et al, 1988 ). Hence, the average production of these compounds by host plants is likely to be infl uenced by the net eff ects on herbivore performance and on the total amount of damage received by plants.…”