INCIDENCE OF A SEVERE BUD BORER IN CARNATION (DIANTHUS CARYOPHYLLOUS L.) CV. CHABAUD MIX IN THE UPPER BRAHMAPUTRA VALLEY AGRO-CLIMATIC CONDITIONS OF ASSAMTADAR JAMJA, SUNIL BORA, RUTHY TABING AND SHAIK FAHEEM AKHTARAbstract The genus Helicoverpa is a polyphagous insect belonging to the order Lepidoptera that creates havoc in range of crops worldwide and is one of the most important and serious insect pests in carnation. During the field experiment of the Chabaud carnation (Dianthus caryophyllous L.) in the horticultural research farm of Assam Agricultural University, Jorhat, Assam, (India) during 2023, Helicoverpa armigera was found ravaging the carnation crop in the experimental field. The present preliminary study sought to examine the correlation between pest infestation and prevailing weather conditions. The sporadic occurrence (0.73%) of the pest started on 13th January and became widespread in the following months. The peak infestation was observed during March and April, and the maximum incidence (18.62%) was recorded from 1st April to 15th April. There was a positive and strong correlation between the incidence (%) of bud borer and minimum temperature (r= 0.90) and rainfall (r= 0.76). Likewise, the maximum RH had a negative and strong correlation (r= 0.74) with borer incidence (%). Meanwhile, the maximum temperature had a positive and moderate correlation (r= 0.67). Additionally, the minimum RH (r= 0.39) and bright sunshine hours (r= -0.36) had weak correlations with bud borer incidence (%). The present study found that the prevailing environmental conditions, the minimum temperature and average mean rainfall in particular had a significant influence on the incidence of insects on chabaud carnation. Bud borers cause serious havoc and damage to the developing flower bud in all stages, piercing, penetrating and feeding inside the bud, eventually leaving the flower bud hollow, empty, redundant and unproductive. |