Field reaction to pests of rainfed rice varieties cultivated under weeded and unweeded conditions

Issue Date

10-2013

Abstract

The experiment was conducted in 2011 dry season (DS) at the farmer's field (rainfed area of 1300 m2 researcher-managed, area surrounded with various crops which ideally serve as refuge for natural enemies) in Nilasin 1st, Pura, Tralac. Ten varieties (7 newly registered rice varieties for rainfed lowland:NSIC 2011 Rc282, NSIC 2011 Rc276, NSIC 2011 Rc280, NSIC 2011 Rc278, NSIC 2011 Rc274, NSIC 2011 Rc272, NSIC Rc192,); and 3 popular varieties (NSIC Rc222, PSB Rc 18, PSB Rc82) and a farmer's variety (NSIC Rc128) were each transplanted 24 days after seeding in 20.8 m2 plots, laid out in RCBD and replicated twice in weeded and un-weeded set-ups. In the unweeded set-up, the weeds were removed manually at 20, 40, 60 days after transplanting and no herbicide was applied. Presence of insect pests and diseases was monitored on each variety from both set-ups and three growth stages (vegetative, maximum tillering and maturity). Fertilizer application was based on the farmer's practice. At vegetative stage, leaf blast infection and deadheart (caused by stemborers) were relatively the most common pest damage observed, while at reproductive stage bacterial leaf blight became common. Green leafhopper population was high during this growth stage. Most pest constraints (diseases and insects) especially sheath blight and stemborers causing whiteheads appeared during the maturity stage in both weeded and unweeded set-ups. Other diseases such as panicle blast, sheath rot, brown spot, false smut and other defoliators were observed but at a very low level and in one or two rice varieties only. Arthropod populations gauges using sweep net at all plant growth stages were generally low but comparably higher in the unweeded plots. The variety NSIC 2011 Rc278 (Sahod Ulan 5) yielded 0.765 t/ha-1 (28.75) higher in unweeded plots. It may have the ability to compete with weeds, but this observation needs further study. Furthermore, this variety incurred the lowest (1%) stemborer damage (whitehead) in unweeded, and the highest (22%) damage in weeded plots.

Source or Periodical Title

The Philippine Entomologist

ISSN

0048-3753

Volume

27

Issue

2

Page

201-202

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

PESTS OF PLANTS; PLANT DISEASES; RAINFED FARMING; WEED CONTROL; PEST CONTROL

This document is currently not available here.

Share

COinS