The false codling moth: behavioral determinants and habitat interactions in fruit entry and soil pupation

The false codling moth (FCM), Thaumatotibia leucotreta, is a pest of several crops. We investigated the influence of fruit type (pomegranate, clementine and avocado) and location on neonate entry, the time required for penetration, tissue colonization patterns, the influence of larval location on trees on pre-pupal behavior, and the effects of soil type and moisture on pupation success. Significantly more larvae penetrated clementine and two pomegranate cultivars than the two avocado cultivars. Despite good hatching success, no more than seven larvae per clementine fruit were observed nine days after infestation, and by the time the fruit was abandoned for pupation, an average of fewer than two larvae remained per fruit. Larvae incorporated soil particles into their cocoons when pupating in soil, while no external materials were used when pupation occurred on leaf surfaces. Larvae pupated close to the soil surface; those seeking lower soil moisture levels were more likely to burrow and consistently preferred dry over moist soil for pupation. Given the short interval between hatching and fruit penetration, and the lack of evidence that FCM neonates feed externally prior to entry, microbial control preparations may be most effective during hatching, particularly during eggshell consumption. Furthermore, the frequent tendency of FCM to pupate on or near the soil surface may limit the effectiveness of soil-dwelling entomopathogens.