Feeding Deterrence and Inhibitory Effects of Bee Balm (<i>Monarda didyma</i>) Leaves on Fall Armyworm

Abstract

The fall armyworm [Spodoptera frugiperda (J.E. Smith)] is a serious pest of many field and horticulture crops. Because of the many advantages for the use of plant-derived pesticides, we tested whether bee balm (Monarda didyma L.) leaves could have feeding deterrence on fall armyworm. When S. frugiperda larvae (neonates and instars 3–4) were supplied with freshly harvested leaves of Zea mays L. (corn), bee balm, or Melissa officinalis L. (lemon balm) for 9 days, 94% of the insects survived on corn leaves, yet, only 0.96% and 48% of the insects survived on bee balm and lemon balm leaves, respectively. For the larvae that survived, their growth on bee balm and lemon balm was significantly reduced (P < 0.001) compared to larvae fed corn leaves. When a choice between corn and bee balm leaves was given, the insect preferred corn leaves. The nature of the feeding deterrence was likely phytochemical rather than structural since fall armyworm larvae reared on an artificial diet mixed with macerated bee balm leaves were significantly (P < 0.05) inhibited when compared to those reared on an artificial diet mixed with macerated corn leaves. Our results suggest that there is potential for the use of bee balm for fall armyworm control.