Efficacy of goatweed (Ageratum conyzoides Linn.) extract against cabbage head caterpillar (Crocidolomia pavonana F.) in pechay (Brassica rapa L.)

Abstract

The study was conducted from April 9 to May 9, 2018 at the back field of Lenwood Edge Building. The objective of the study was to assess the efficacy of Ageratum conyzoides Linn. against Crocidolomia pavonana F. in pechay. Specifically, to count the number Crocidolomia pavonana F infesting pechay, rate its damage, determine plant height, the number of leaves, the presence of other insects, the percentage of marketable plant and compute its yield per hectare basis. The experimental treatments were laid out in a randomized complete block design with three replications. The treatments were composed of 15% and 20% whole plant extracts and 15% and 20% leaf extracts of Ageratum conyzoides Linn. Tap water was used as control treatments. The treatments did not affect the number of Crocidolomia pavonana F. infesting the plants. The least insect damage ranging from 0-5% was found in plants treated with 15% and 20% whole plant aqueous extract. Treatments did not significantly affect the plant height and number of leaves until at the 4th week of transplanting. Average plant height in treated plants did not vary, control plants was significantly lower. Plants sprayed with 15% and 20% whole aqueous extracts (WAE) plants had the most leaves of 7.13 and 7.33 respectively. Plants in 15% and 20% WAE had the highest percentage marketable yield of 78.33%. A significantly higher yield of 2557.50 kg/ha, 2667.50 kg/ha was obtained from 15 and 20% WAE. Results showed that 15% and 20% concentrations of A. conyzoides whole aqueous extracts can be used to control C. pavonana in pechay.