A Bioassay Differentiates Resistance to the Colorado Potato Beetle on Tomatoes1

Schalk, J. M.; Stoner, Allan K.

doi:10.21273/jashs.101.1.74

Cited by 28 publications

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“…Schalk and Stoner (16) found that CPB larvae consumed senescent lower leaves of L. hirsutum faster than juvenile upper leaves from the same plant. In the high-tomatine wild species L. pimpinellifolium (L.) Mill., Sander and Angermann (15) found that the tomatine content was highest in shoot tips, and that the content was higher in old leaves than in middle leaves.…”

Section: Resultsmentioning

confidence: 99%

“…Variations in the feeding rate of the beetle populations on consecutive days of testing, due to handling, aging and changes in the sex ratio (16), could mask a relationship between tomatine content and feeding rate. Leaves from 2 constant-age L. esculentum check plants (35-41 days old, 16-hr daylength) were included in each experiment to detect any such variations.…”

Section: Resultsmentioning

confidence: 99%

“…Eighteen disks from each of 2 of these young check plants were included in each test of the L. esculentum and L. hirsutum plants grown in different daylengths, at each of the 3 stages of development. Disks from these check plants were included in the tests to measure variations in the feeding rate of the beetle population, due to handling, aging, and changes in the sex ratio (16). Plants were given no pesticide or fertilizer and only routine watering.…”

Section: Methodsmentioning

confidence: 99%

“…In the published studies that demon strated that tomatine is a deterrent to beetle feeding (17,18), potato leaf disks were infiltrated with tomatine, and potato leaf disks infiltrated with water were used as checks to calculate the percent inhibition of feeding caused by tomatine. Using the same methodology (18) and new bioassay (16), we vacuum infiltrated L. esculentum (C28) leaf disks from greenhouse plants with weakly acid (pH of 5.5-5.9) tomatine solutions at concn of 0.4, 0.8, and 1.0 mM in order to determine whether or not infiltrated tomatine also inhibited feeding on tomato leaf disks. Concentrations of tomatine in the infiltrated leaf disks were determined by weighing the disks prior to, and again after infiltration with the tomatine solutions of known concn (18).…”

Section: Bioassays the Bioassay Technique Developed By Schalk Andmentioning

confidence: 99%

“…Schalk and Stoner (16) recently developed an improved bioassay for measuring resistance to the CPB and showed that 2 introductions of Lycopersicon hirsutum were highly resistant. They also observed variation in the level of resist ance in these wild tomato plants that was due to variation in the greenhouse environment and the position of the leaves on the plant.…”

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Effects of Daylength and Maturity of Tomato Plants on Tomatine Content and Resistance to the Colorado Potato Beetle1

Sinden¹,

Schalk²,

Stoner³

1978

J. Amer. Soc. Hort. Sci.

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Plants of Lycopersicon hirsutum Humb. & Bonpl., which were resistant to the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), and plants of susceptible Lycopersicon esculentum Mill, were grown in controlled environment chambers with 8- or 16-hour daylengths. Rates of feeding by CPB on lower leaves from these plants were measured at 3 stages of plant development and tomatine contents of the leaves were determined. Leaves from young plants were more susceptible to CPB feeding than leaves from flowering or mature plants, and tomatine content was lower in the young leaves. The daylength also had significant effects on tomatine content, feeding rate, and the resistance expressed by L. hirsutum plants. For all plants in the experiment, tomatine content and feeding rate were negatively correlated (r = −0.643, p = 1%). Feeding was inhibited 20–80% when tomatine was infiltrated into tomato leaf disks at concentrations between 65 and 165 mg/100 g fresh weight. The results suggest that a high tomatine content in leaves of L. hirsutum or L. esculentum inhibits CPB feeding.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Bioassays the Bioassay Technique Developed By Schalk Andmentioning

confidence: 99%

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confidence: 99%

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