Development of a screening technique for sugarcane tolerance to damage of white grub, Leucopholis irrorata Chevrolat

Issue Date

12-2005

Abstract

A practical screening technique for sugarcane tolerance to damage of white grub was developed using commercial varieties PS-3, VMC 86-550, VMC 71-238, PHIL 75-44 and CP 29-116. This study focused on (a) appropriate age of test plants; (b) minimum number of test plants/variety; (c) parameters for comparing varietal tolerance; (d) appropriate grub infestation level; and (e) whether to conduct evaluation in the field or greenhouse. Among the six age groups tested (30, 60, 90, 120, 150, and 180-day old plants), the 90-120-d-old plants were most appropriate since signs of recovery from grub feeding damage were manifested within a shorter period upon termination of grub infestation. Maximum damage may be sustained but still capable of root regrowth whether based on 5, 10, 15 or 20 test plants/entry, with CP 29-116 as the most tolerant and PHIL 75-44, the least. Five plants per variety are adequate for identifying highly tolerant entries. However, for higher precision of identifying highly tolerant entries, thirty-six plants per variety are needed for evaluation. Reduction in damage symptoms on above-ground plant parts and plant height increase can be used as indicators of tolerance. Above-ground damage symptom was positively correlated with root damage. Five second instar grubs/plant was adequate for detecting significantly different tolerance levels. It was found more practical to conduct varietal screening for tolerance to L. irrorata in a greenhouse.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Volume

88

Issue

4

Page

440-452

Document Type

Article

Language

English

Subject

Host plant resistance, Leucopholis irrorata Chevrolat, Screening technique, Tolerance, White grub

Digital Copy

None

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