Investigation On Pest Species Of Liriope Muscari(Desne) Bailey And Integrated Pest Control Of Main Species

Liriope muscari (Decne.)Bailey is one of the most important herb which is used widely in construction of garden in south China, which belongs to Liliaceae, Liriope genus. As ornamental herbs, they are planted and applied in the flower border, retirements or border of garden and forest because of their perennial and evergreen leaves, and beautiful flowers and fruits. Sometimes, they are applied as slope protection plants in the conservation of water and soil, and afforestation of area under urban overpass and residential green. Co ndition permitting, the ornamental and herbal medicine garden should be set up to satisfy science populariz ation education. But in recent years, the cultivated area is increasing with it’s widespread application in gardens of Fujian province. But the damage level is getting more and more dangerous because there isn’t any matched maintaining measures, and the situation also have not attached great importance by the owner of garden. Especially since2009, the growth and landscape value of L. muscari were affected by their diseases and pests because of abrupt increasing of population. From past documents, little report can be found to guide the management of these pests, so we have no idea on how to control them effectively. Consequently, this paper deal with investigation on pest and disease species of L. muscari, occurrence regularities and reasons to guide us how to develop some pollution-free control technologies and alleviate their negative aspects. They are as follow:1. Main species of disease and pest in L. muscari38specimen from different parts of L. muscari were investigated and collected to identify the main species of disease and pest. The results showed that main diseases in leaves of L. muscari include Pleospora sp.,Altemania tenuis Nees, sooty molds, etc. while Pleospora sp.is the most importance disease with forty to fifty percent infection rate per individual and seventy to eighty percent infection rate per seedbed. Main pests include scale insects, aphids, grubs, etc. While Pinnaspis aspidistrae (Signoret) is the most importance pest which can be suck the leaves, fruits and flowers directly, in addition. It can be carry and transmit some diseases, leading to compound damage. In conclusion, Pleospora sp.and P. aspidistrae should be studied in detail to explore their occurrence dynamics, put forward rational, safe, timely and effective measures respectively to control them.2. Main reasons of disaster caused by diseases and pestsMain reasons of disease and pest disasters were analyzed based on the regular and historical investigation on-the-spot. Firstly, the seedlings were planted in seedbed without any disinfection, and the last diseased and infected plant were disposed improperly, above mentioned activities both provided pathogeny source of next year. Secondly, vector insect just like scale insects broke out and led to compound damage directly and indirectly. Thirdly, too closing density of seedling which led to shade and wet environment create batter condition for pathogeny. Lastly, higher temperature with windy and rainy day, were also benefit for spreading and invading of pathogeny in summer, and the drainage should be in good condition in this season.3. Biological characteristic of P. aspidistraeP. aspidistrae is the most importance pest on L. muscari. In order to control this scale insects and their transmitting pathogeny, it is critical and basic to control this scale pest. These pests were studied in Lab by rearing experimental population. The results showed that in their range of temperature resistance, the higher the temperature was, the faster the insects developed. The Least good method was adopted to determine the developmental threshold temperature and effective accumulated temperature of all generation, the results showed that they were17.94℃and318.8℃19.1day degree respectively. Furthermore,2generations were predicted theoretically based on climate data of Fujian province. This insect has dichotocarpism and overlapping of generation. Different instars of pests could overwinter and suck host in the winter per year, then laid it’s eggs. Different parts of hosts had different population density of insects, and their order is fruits>leaves>stems>flowers, most of them preferred to roost in fruits and leaves, and these places maybe their main overwintering location.4. Pleospora sp.and it’s controlThis disease mainly occurred at the apex or edge of leaves, then emerged some fawn-coloured stain in initial stage, then extend downward to emerge some irregular scabs. At last, all scabs turned dark and putresced at the apex after scabs turned brown or black brown. By means of freehand section and microscopic examination, the pathogeny belongs to Ascomycota, Pleosporales, Pleospora, and stroma is half buried by plant tissue with cylindrical perithecium, several ascuses, and8coloured ascospores in each ascus. The pathogeny can be survived in whole growth season of host, including emerging in March, prevailing from May to August, degenerating from October to November. These pathogeny overwintered in diseased of infected plants of soil, then invaded plant directly of through wounds of host. Meanwhile, some pathogeny were detected from1-2instar nymph, splashing rain, soil and newly planted seedlings, so these infection source should be taken measure to deal with.The control experiment resulted showed that morbidity of seedlings and individual leaf were lower than contrast which indicated fungicide playing important role to control disease.50%Dithane and80%Carbendazim were both recommended to deal with newly seedling and seedbed with dose1g/m2. One antibiotics Duokanjunshu was also recommended to protect the seedlings with dose lg/m2, another antibiotics Duoyangqing can be sprayed to protect or cure leaves. Spray5. Other control measuresGarden, biological and horticultural technology should be integrated and applied to control pests and diseases of garden based on characteristics and reasons of occurrence. Firstly, the ornamental plants should be allocated reasonably to single out some higher resistance species to apply in the practice. Secondly, some infested Liriope muscari were not permitted to plant in the garden, especially in some shade places. Some health and strong plants should be selected to apply in the practices. The succession of crops were also be taken into consideration. Thirdly, the management level should be improved by making sanitation, pruning and loosening the soil to destroy the dormancy environment places of pests. Lastly, some native enemies should be protected and applied by mass rearing and artificial moving to increase the population of nature enemies and control the pest once for all.