Exogenous applied defense hormones regulate broad mite population growth in an azalea leaf disc assay

Plants possess a defense network based on defense related phytohormones that translate stresses of biotic or abiotic origin into plant defense responses. Herbivore attack is known to induce jasmonic (JA) or salicylic acid (SA) mediated plant defenses. Here we performed preliminary tests to evaluate the interaction between the broad mite, Polyphagotarsonemus latus (Acari: Tarsonemidae) and pot azalea, Rhododendron simsii hybrid. The broad mite is a polyphagous pest causing damage on many commercial crops. On pot azalea few mites can cause considerable aesthetic damage. Exogenous SA and methyl jasmonate (MeJA) was applied on floating leaf discs of pot azalea to evaluate the population growth in broad mite. The preliminary data suggest that application of MeJA results in a slower increase of the broad mite population. The application of SA tends to promote broad mite population growth. For both exogenous applied defense related compounds, the effect depended on the dose applied.