Within-leaf differences in nutritive value and defence mechanism in chrysanthemum to the two-spotted spider mite (Tetranychus urticae)

Eight cultivars of the ornamental crop Gerbera jamesonii Bolus (Asteraceae) were compared in host plant suitability for the two spotted spider mite Tetranychus urticae Koch (Acarina: Tetranychidae). This was done by determining the intrinsic rate of population increase, rm, of spider mites on leaf discs of plants from each of the cultivars. Large differences in rm values were found, ranging from 0.088/day on cultivar Bianca to 0.242/day on cultivar Sirtaki. This variation in rm was mainly caused by differences in developmental time of the spider mites. We assessed the performance of spider mites on young and old leaves of the two gerbera cultivars Bianca and Sirtaki. On Sirtaki the spider mites had a shorter developmental time and higher peak oviposition rate on young leaves than on old leaves. However, on Bianca such an effect was not found. We also determined the performance of two spider mite strains on the resistant gerbera cultivar Bianca. We compared the rm of a strain that had been reared on this cultivar for approximately half a year with the rm of a strain that was reared on bean. The rm of the strain that was reared on cultivar Bianca increased to 0.208/day, which is however still substantially lower than the rm on the susceptible cultivar Sirtaki.

Section: Introductionmentioning

confidence: 78%

Intrinsic rate of population increase of the spider mite Tetranychus urticae on the ornamental crop gerbera: intraspecific variation in host plant and herbivore

Krips

Witul²,

Willems

et al. 1998

“…The young leaves, where the majority of the growth damage occurs, are especially attractive to thrips because developing tissue has a high content of nitrogen, which is a limiting nutrient for many herbivores (Mattson, 1980;Kielkiewicz & van de Vrie, 1990). Kielkiewicz & van de Vrie (1990) indeed observed that young chrysanthemum leaves contained a higher concentration of nitrogen and soluble proteins than mature leaves. However, the optimal defense theory predicts that the younger, more valuable plant parts are better defended against herbivores than the less important older leaves (Zangerl & Bazzaz, 1992;van Dam et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

“…The most apparent interaction between plants and leafminer larvae is via the ingestion of mesophyll and thus most likely via plant secondary metabolites. Kielkiewicz & van de Vrie (1990) showed that chrysanthemum cultivars resistant to spider mites contained significantly more mono-and poly-phenols than susceptible ones. de Jong & Rademaker (1991) showed that in chrysanthemum the variation in host plant resistance to celery leafminer was also based on a chemically unsuitable diet; however, no specific compounds were identified.…”

Section: Discussionmentioning

confidence: 99%

Cross‐resistance of chrysanthemum to western flower thrips, celery leafminer, and two‐spotted spider mite

Kos

Klinkhamer

Leiss

2014

Chrysanthemum [Chrysanthemum 9 morifolium Ramat. (Asteraceae)] is one of the economically most important greenhouse ornamentals worldwide. A major constraint in chrysanthemum production is adequate pest management, requiring the use of different tactics, such as improving host plant resistance, in the framework of an integrated pest management (IPM) approach. In this study, we investigated cross-resistance of chrysanthemum to its three major pests: western flower thrips [Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)], celery leafminer [Liriomyza trifolii (Burgess) (Diptera: Agromyzidae)], and two-spotted spider mite [Tetranychus urticae Koch (Acari: Tetranychidae)]. We quantified resistance to each pest by performing greenhouse bioassays with a broad range of chrysanthemum types from commercial germplasm provided by Dutch breeding companies. Considerable variation was detected among the chrysanthemum cultivars in thrips silver damage and growth damage, leafminer damage, measured as number of mines and pupae, and spider mite numbers and damage. We observed significant positive correlations between thrips damage (both silver and growth damage) vs. leafminer numbers (both mines and pupae), and between leafminer numbers (both mines and pupae) vs. spider mite numbers. Our results indicate an overlap in resistance to all three herbivores. The important implications of this result for chrysanthemum breeding are discussed.

“…The negative partial correlation between both types of damage suggests that thrips made a choice between young and old leaves to feed on. Young chrysanthemum leaves have both more primary metabolites and more secondary metabolites than old leaves (Kielkiewicz & van de Vrie, 1990). Differences between young and old leaves must be studied in more detail to explain the choice made by thrips.…”

Section: Discussionmentioning

confidence: 99%

Genetic variation in chrysanthemum for resistance to Frankliniella occidentalis

Jager

Butôt

Klinkhamer

et al. 1995

In a choice‐experiment, 42 chrysanthemum cultivars were screened for resistance to Frankliniella occidentalis (Pergande). Oviposition preference, two types of feeding damage and thrips numbers per flower were recorded as measures of resistance. A large genetic variation in thrips resistance was found among the cultivars screened. The amount of feeding damage was strongly determined by oviposition preference. Besides, a positive correlation was found between the oviposition preference in non‐flowering chrysanthemums (number of eggs) and flowering chrysanthemums (number of thrips per flower). Thrips feeding on young, developing tissues, causes growth damage because affected cells are unable to expand and leaves become distorted. Thrips feeding on older, expanded leaves causes cells to become filled with air, resulting in ‘silver’ damage. The amounts of growth‐ and ‘silver’ damage were negatively correlated suggesting that thrips chose either young or older leaves to feed on. The order of resistance among cultivars did not change during the experiment. In order to get more insight in resistance mechanisms the influence of some plant‐ and flower characters on resistance was examined. The plant characters height, number of leaves, flower production and flower weight were all negatively correlated with resistance. It is suggested that tall chrysanthemum cultivars with many and large flowers may invest less in defence than smaller cultivars, and therefore are more damaged by thrips.