Unusual population increase of woolly bear caterpillars, Spilosoma sp. (Arctiidae: Lepidoptera) at Los Baños and vicinity in 2010

Issue Date

7-2011

Abstract

The woolly bear caterpillars, Spilosoma sp, are usually found in Ipomea obscura (L.)Ker-Gaw). In 2010, there was sudden and unusual increase in population of this pest. The caterpillars attacked various crop such as eggplants, corn, okra, patola, ube, papaya, and a number of weeds species. The caterpillars even entered homes and pupated in ceilings, cracks, and crevices. It caused anxiety to many people due to the menacing thick hair appearance. The prolonged dry spell in 2010 could have triggered the aggregation of adults in remaining green areas and led to subsequent population increase. We compared the 2010 agrometeorology data from that of 2005-2009 at the Central Experiment Station, UP Los Baños. The results showed the low rainfall from February (3.0 mm) up to May (9.1 mm) in 2010 as compared to the previous four years. The rainfall also increased in June to July 2010 at 171.2 mm and 762.5 mm, respectively. This dry spell followed by two et months could have led to the population increase of Spilosoma sp. This phenomenon is similar to the locust outbreak in Central Luzon in the 90's where dry environment due to ash fall predominated in breeding areas followed by strong rainfalls led to population increases and subsequent migration/infestation in the central plains. The population increase of woolly bear caterpillar coincided with the population outbreaks of armyworms, Spodoptera Sp. semi-loopers and other lepidoterous species in various parts of the country.

Source or Periodical Title

Transactions of the National Academy of Science and Technology

ISSN

0115-8848

Volume

33

Issue

1

Page

129

Document Type

Article

College

College of Agriculture and Food Science (CAFS)

Language

English

Subject

Insect pests; Population increase; Los Baños (Laguna)

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