Ecology of the Maize Orange Leafhopper, Cicadulina bipunctata (Melichar) (Hemiptera: Cicadellidae)

Abstract

Recent global warming has caused the maize orange leafhopper, Cicadulina bipunctata (Melichar), to proliferate in Kyushu, Japan. This leafhopper feeds on several species of poaceous plants. Some host plants such as maize, rice, wheat and oats show abnormal growth, characterized by stunted growth and swelling (upheaving) of leaf veins when attacked by C. bipunctata. This abnormal growth is not caused by a virus or phytoplasma, but by the injection of chemical(s) from the leaf hopper into the plants. In central and southern areas of Kyushu, serious damage arising from this abnormal growth is known as maize wallaby ear symptom (MWES) and occurs on forage maize during the second cropping season (from late June to November). The degree of MWES is highly dependent on the level of infestation (period and density) by C. bipunctata, and since C. bipunctata density is quite low until mid-July, the earlier seeding of the second crop and the use of MWES-resistant varieties is an effective way to avoid damage from MWES. This leafhopper shows a unique relationship between plant and herbivores because MWES induction by adult C. bipunctata helps improve the development of their offspring through the accumulation of amino acids on the host plant.

Orange Leafhopper Cicadulina bipunctata Feeding Induces Gall Formation Nitrogen Dependently and Regulates Gibberellin Signaling

“…Because nymphs hatched during the assay, C. bipunctata females were not suitable for the bioassay; hence, only males were used ( Figure S1 ). We first confirmed whether the wallaby ear symptoms induced in rice seedlings (Nipponbare variety) were similar to that of maize seedlings [ 9 , 21 ]. Agar, half-strength Murashige and Skoog (MS), MS, and peat moss were used as media for the bioassay.…”

“…It has been reported that C. bipunctata feeding induces wallaby ear symptoms, namely growth suppression and gall formation characterized by severe swelling of leaf veins, on various Poaceae including the major staple crops maize, rice, and wheat [ 21 ]. In agreement with previous studies, the present results showed that C. bipunctata induces both symptoms in rice seedlings [ 9 , 21 ]. In all tested media, gall formation score tended to increase as nutrient levels also increased, and a correlation was found between gall formation and N content.…”

Control strategy for maize wallaby ear symptom based on a quantitative forecasting model for the maize orange leafhopper, Cicadulina bipunctata

“…MWES becomes serious when young maize plants are exposed to long term infestation by large numbers of C. bipunctata. Some other poaceous plants such as rice (Oryza sativa), wheat (Triticum aestivum) and Italian ryegrass (Lolium multiflorum) show stunted growth together with swelling of leaf veins, similar to the symptoms of MWES on maize, when C. bipunctata feeds on them (Maramorosch et al, 1961;Matsukura and Matsumura, 2013).…”

Future risk of the maize orange leafhopper, Cicadulina bipunctata, and maize wallaby ear symptom in temperate Japan

“…In Kyushu Island, Japan, C. bipunctata had been recorded in only one of seven prefectures (Kumamoto prefecture) for more than 70 years since the first record in the 1910s (Matsumura 1914), but it is now present in all seven prefectures following gradual range expansion that probably started in the late 1980s . MWES has been a serious problem in the central and southern plains areas of the island since the early 2000s (Kumashiro et al 2012;Matsukura and Matsumura 2013). The leafhopper was also found in Shikoku Island, east of Kyushu, in 2011 .…”