Table 2. Investigation of the occurrence of major pests on host plant (2018−2020)

Host plant	Hyphantria cunea (Drury)	Lycorma delicatula	Ricania shantungensis	Metcalfa pruinosa	Ceroplastes rubens	Ceroplastes japonicus (Green)	Monema flavescens	Cantao ocellatus
1. Juglans mandshurica Maxim.	++
2. Ailanthus altissima (Mill.) Swingle		+++
3. Forsythia koreana (Rehder) Nakai		+	+
4. Diospyros kaki Thunb.	+++		+				++
5. Ilex serrata (Thunb)	+++				+++
6. Taxodium distichum (L.) Rich.	+
7. Nandina domestica (Thunb.)			+
8. Zelkova serrata (Thunb.) Makino	+
9. Raphiolepis indica var. umbellata (Thunb.)	+		+
10. Acer palmatum (Thunb.)	+		+
11. Camellia japonica. L			++	+	++	+
12. Wisteria floribunda			+
13. Quercus robur							++
14. Prunus mume Siebold & Zucc. f. mume	++		+
15. Melia azedarach var. japonica		+++	+
16. Metasequoia glyptostroboides			+
17. Osmanthus fragrans (Thunb.) Lour			+
18. Hibiscus syriacus L.			+
19. Fraxinus rhynchophylla Hance	++
20. Populus deltoides Marsh.	++	+	+
21. Lagerstroemia indica L.			+
22. Salix koreensis Andersson	++
23. Platanus occidentalis L.	+++
24. Prunus serrulata var. spontanea	+++		++				+
25. Firmiana simplex (L.) W. F. Wight		+
26. Weigela subsessilis (Nakai) L. H. Bailey	+		+
27. Morus alba L.	+++		+++
28. Prunus persica (L.) Batsch f. persica	+		+
29. Euonymus japonicus Thunb.			+
30. Cornus officinalis Siebold & Zucc.	++		+++
31. Robinia pseudoacacia L	+		+
32. Viburnum odoratissimum var. awabuki			+
33. Mallotus japonicus (L. f.) Mull. Arg.	+	+						+++
34. Ginkgo biloba L.			+
35. Chionanthus retusus Lindl. & Paxton	++
36. Quercus spp.		+
37. Rhododendron schlippenbachii Maxim.						++
38. Liriodendron tulipifera			+
39. Vitis vinifera L.		+
40. Pyracantha angustifolia (Franch.) C. K. Schneid	++					+
41. Ilex cornuta Lindl. & Paxton			+		++
42. Euonymus alatus (Thunb.) Siebold			+
43. Kerria japonica (L.) DC. f. japonica			+
44. Photinia glabra (Thunb.) Maxim			++	+
45. Corylopsis coreana Uyeki.			++
Total	20 (9)	8 (6)	29 (4)	2	3 (3)	3 (3)	3 (2)	1 (1)

Degree of occurrence: +, few; ++, medium; +++, sever in 2018, 2019. +, ++, +++, in 2020.