Howardia biclavis (Comstock)

Lázaro-Castellanos, Carlos, González-Hernández, Héctor, Nápoles, Jesús Romero-, Ortega-Arenas, Laura D., Equihua-Martínez, Armando & Ochoa-Ascencio, Salvador, 2023, Armored scale insects (Hemiptera: Diaspididae) associated with avocados (Persea americana) in México’s main production areas, with keys for identification and natural enemies, Zootaxa 5357 (2), pp. 241-269 : 259-260

Howardia biclavis (Comstock)

Chionaspis? biclavis Comstock 1883: 98–100 .

Chionaspis biclavis detecta Maskell 1895: 49 .

Howardia biclavis (Comstock) ; Berlese & Leonardi 1896: 348.

Chionaspis (Howardia) biclavis (Comstock) ; Maxwell-Lefroy 1902: 250.

Howardia biclavis detecta (Maskell) ; Fernald, 1903: 227.

Megalodiaspis biclavis (Comstock) ; Paoli 1915: 256.

Howardia (Chionaspis) biclavis (Comstock) ; Ramakrishna Ayyar 1921; 353.

Field diagnosis. Adult female scale cover circular and convex, 2.5‒3.0 mm in diameter, yellowish white to brown, with fibrous appearance, exuviae subcentral. Body of live adult female membranous, slightly brown, or gray, 2.4‒ 2. 9 mm long, occupying almost the entire diameter of the waxy cover.

Discussion. Several studies record that adult female Ho. biclavis can penetrate the epidermal tissue of its hosts although judging by their morphology, the crawlers seem not to have this capacity; on the other hand, still little is known about the biology of this species ( García Morales et al. 2016).

Habits on the hosts. Howardia biclavis was found on branches individually or in small groups of no more than three individuals; it was found associated with other species of diaspidid scales such as Chr. dictyospermi , H. diffinis , H. lataniae and P. parlatorioides .

Hosts. The scale is a polyphagous species that attacks members of 196 genera belonging to 69 plant families, including several hosts of economic importance such as mango, soursop, papaya, lemon, avocado, eggplant, and tea, among others ( Watson 2002; García Morales et al. 2016). In this study it was found associated only with Hass avocado.

Distribution. Howardia biclavis is widely distributed; its presence is known in 72 countries on five continents ( Watson 2002; García Morales et al. 2016). In México, it has been collected on Hass avocado in the municipality of Los Reyes, Michoacán (González Hernández, pers. comm., 2019). In the present study it was found in the following states and orchards: Colima: La Calma; and Nayarit: Camino Cerro San Juan, Camino a Cofradía and El Aguacate.

Natural enemies. Among the natural enemies that regulate Ho. biclavis are the following: Aphelinidae : Aphytis diaspidis , Aph. proclia , Aph. theae , Marietta busckii , Pteroptrix albifemur ; Encyrtidae : Plagiomerus sp. , Zaomma sp. ; and Signiphoridae : Signiphora dozieri ; also, Phlaeothripidae : Haplothrips sp. ( García Morales et al. 2016; Noyes 2019). In the present study, the parasitoids Aph. holoxanthus (1M) and S. perpauca (1F) were reared from Ho. biclavis .