Morphological description of the mouthparts of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae).

Scanning (SEM) and transmission (TEM) electron microscopy were used to elucidate the morphology of the rostrum, as well as the mandibular and maxillary stylets of the psyllid Diaphorina citri, vector of phloem-inhabiting bacteria associated with citrus huanglongbing (HLB) disease. D. citri has a cone-shaped rostrum that extends behind the pair of prothoracic coxae. The stylet bundle comprises a pair of mandibular (Md) and maxillary (Mx) stylets with a mean length of 513.3 µm; when retracted, their proximal portions form a loop and are stored in the crumena (Cr). Serial cross-sections of the rostrum revealed that the mandibles are always projected in front of the maxillary stylets. The two maxillary stylets form the food and salivary canals, with diameters of 0.9 µm and 0.4 µm respectively. These two canals merge at the end of the stylets forming a common duct with a length of 4.3 µm and a mean diameter of 0.9 µm. The acrostyle, a distinct anatomical structure present in the common duct of aphid maxillary stylets, was not observed by TEM in the ultrathin cross-sections of the common duct (CD) of D. citri. This study provides new information on D. citri mouthparts that may help to understand the feeding behaviour of this important vector of HLB-associated bacteria.

Whitefly resistance traits derived from the wild tomato Solanum pimpinellifolium affect the preference and feeding behavior of Bemisia tabaci and reduce the spread of Tomato yellow leaf curl virus.

Breeding of tomato genotypes that limit whitefly (Bemisia tabaci) access and feeding might reduce the spread of Tomato yellow leaf curl virus (TYLCV), a begomovirus (genus Begomovirus, family Geminiviridae) that is the causal agent of tomato yellow leaf curl disease. TYLCV is restricted to the phloem and is transmitted in a persistent manner by B. tabaci. The tomato breeding line ABL 14-8 was developed by introgressing type IV leaf glandular trichomes and secretion of acylsucroses from the wild tomato Solanum pimpinellifolium accession TO-937 into the genetic background of the whitefly- and virus-susceptible tomato cultivar Moneymaker. Results of preference bioassays with ABL 14-8 versus Moneymaker indicated that presence of type IV glandular trichomes and the production of acylsucrose deterred the landing and settling of B. tabaci on ABL 14-8. Moreover, electrical penetration graph studies indicated that B. tabaci adults spent more time in nonprobing activities and showed a reduced ability to start probing. Such behavior resulted in a reduced ability to reach the phloem. The superficial type of resistance observed in ABL 14-8 against B. tabaci probing significantly reduced primary and secondary spread of TYLCV.

Novos hospedeiros para Hemencyrtus herbertii Ashmead (Hymenoptera: Encyrtidae) coletados em Lavras, Minas Gerais / News hosts for Hemencyrtus herbertii Ashmead (Hymenoptera: Encyrtidae) collected in Lavras, Minas Gerais

This study verified the host species of the parasitoid Hemencyrtus herbertii Ashmead (Hymenoptera: Encyrtidae), in Lavras, Minas Gerais, Brazil. The pupae were obtained by the flotation method. They were individually placed in gelatin capsules until the emergence of adult flies or their parasitoids. The overall occurence of parasitism was 6.5 percent. The occurrence of parasitism presented in the hosts Chrysomya megacephala (Diptera: Calliphoridae) and Sarcodexia lambens (Diptera: Sarcophagidae) was 1.3 percent and 29.4 percent, respectively.