Exploring Intercropping Crops With Vine To Control Phylloxera Daktulosphaira Vitifoliae Fitch

Grape phylloxera, Daktulosphaira vitifoliae (Homoptera: Phylloxeridae), is a worldwide pest ofgrapevines. It is native to the northeastern, southwestern, and central United States where it hassuccessfully coevolved with native North American Vitis species. It is a gall-forming pest that attacksthe leaves and roots of grapes. Feeding of Phylloxera does little to affect the health of native grapevinesin eastern North America, but severe viticultural impact of its feeding became evident when it wasimported into France before the1870s. It devastated the European grape, Vitis vinifera L.(Vitaceae:Rhamnales), vineyards first in France, then was spread across the continent, and finally around nearlyevery grape-growing region in the world. It has been the most important pest on grapevines in the worldsince then. Many methods, chemicals, cultural, biological, physical and quarantine, had been trialed,since European vineyards were destroyed by phylloxera since later nineteenth century, even organicfarming was tested recent decade. But only resistant rootstocks, originated from roots of American Vitisspecies and hybrids, adding the quarantines, have been proved to be successful management for the pestand have been used around the world since1930. Researching on other approach of managementstrategies and measures also weakened since then. Though more and more works in the fields ofdetection, quarantine and alternative management has been explored in recent decades, but the moreeffective technologies like resistant rootstocks are far more important by grape industry all over theworld, especially in China because most of vines are planted ungrafted in commercial vineyards.Approaches about multiple cropping, with plants of having insecticidal activity, have been explored tocontrol the pest. The results and conclusions are listed as follow.(1) The impact of aqueous extract of tobacco root and nicotine solution to grape phylloxera wereevaluated by bioassay, and the effects of grape-tobacco intercropping pattern on populations of grapephylloxera and on growth and development of infested vine were studied and evaluated in field. Resultsshowed that aqueous extract of tobacco root and nicotine solution have good biological activity on thepest, its egg hatchability, nymph survival rate, development period, life span and female fecundity weresignificantly affected. In field trial, the populations of grape phylloxera were decreased obviouslycomparing to monoculture pattern and the rate of newly developed root and newly invested roots ofgrape were respectively significantly higher and lower in intercropping patterns than in vinemonoculture. The number of grape phylloxera population on grape roots continued to reduce year byyear and the trees of vine have got renewal gradually, for continuously intercropping with tobacco inthree years. These result confirmed that intercropping grape with tobacco could effectively control grapephylloxera in infested vineyard. The result also indicated that more crops, that could be intercroppedwith gape and have effectiveness to gape phylloxira, should be explored to be an approach ofmanagement measure to control the pest.(2) There are thousands of plants used as Chinese herb medicines, but only94plants of them havebeen evaluated and confirmed containing substances with insecticidal activity, according to reported literatures so far. We selected18kinds of them, according the required condition of intercropping withvine, to test intercropping function in vineyard. The germination rate in soil of vineyard, leaf area, plantheight, seed weight and germination rate of seeds of selected plants were recorded to evaluate if theplants can be growth well with vine. The results showed that achyranthes (Achyranthes bidentata), Aster(Aster tataricus), basil (Ocimum basilicum), purple perilla (Perilla frutescens), Nepeta cataria, mint(Mentha haplocalyx) and Cassia seed (Cassia obtusifolia) have potential to intercrop with grapes invineyard.(3) The impact of aqueous extract of the root of the seven selected plants to grape phylloxera wereevaluated by bioassay, and the effects of intercropping pattern on populations of grape phylloxera andon the rate of newly developed root and newly invested roots of infested vine were studied andevaluated by Potted Plant Test. The results showed that aqueous extract of seven plants have asignificant effect on survival, development and fecundity of grape phylloxera in bioassay, andintercropped with all of seven plants leaded to more new roots, smaller rate of new root damaged andlower population of grape phylloxera. These result confirmed that all of the seven selected plants, thathave insecticidal substances and those activity substances exudated by roots of the plants, could bedelivered to soil and reach and contact the roots and the pest, through roots cross each other. Thebioassay and the Potted Plant Test have the similar results. The achyranthes is the best one, followingare Aster, basil, purple perilla, Cassia seed, Nepeta cataria and mint. The results of Potted Plan Test alsoshowed that the longer the plants intercropped with grape, the better control effects to the pest. Theresults indicated the active substances might be accumulated in the soil and intercropping with thoseplants might have effects to scattering of first instars.Olfactory behavioral responses, of first instars nymphs of grape phylloxera, have tested to aqueousextract of the root of the seven selected plant by bioassay. There is no response of the nymphs to theextracts of the roots. The result indicates the effectiveness of the seven selected plants to grapephylloxera is maybe by the contact or/and stomach toxicity rather than the taste of volatile substances.(4)104chemical compounds of achyranthes root have been analyzed and reported in refereces, butwe got only22from market. We tested the bio-activity of those22chemical compounds to grapephylloxera by bioassay. The results indicated β-ecdysterone is the compound which has insecticidalactivity against grape phylloxera. Aqueous extract of achyranthes root is more effective thenβ-ecdysterone solution at the same dose of β-ecdysterone. This result indicates there is/are maybe otherchemical compounds which have bio-activity or there are chemicals having synergy effects withβ-ecdysterone. We analyzed the contents of achyranthes root from market and the one from tested field.The results indicated they have similar quality.(5) Every plant of5selected plants was inoculated with10important grape viruses by mixedplanting with virus infested grapes and by friction to evaluate if they have opportunity to have/transmitvirus diseases of grapes. RT-PCR test results showed that all of them do not have any of the10important grape viruses. There is no reported reference about the selected plants to be infested orinfection of important grape viruses. The results indicate there is no risk to be infested and transmit important grape viruses, if the5selected plants intercrop with grapes in vineyards.(6) Bioassays of Potted Plant Test, intercropping with grape and leaching solution of rhizospheresoil, had been carried out to evaluate the allelopathic function of the three selected plant to grape. Theresults showed that leaching solution of rhizosphere soil showed some inhibitory effect tobud germination and shoot growth but the difference was not significant, and that intercropping witheach of three did not show inhibitory effect of allelopathic function.The results indicated that grape could be intercropped with achyranthes, aster and basil for at leastone season, but sequential intercropping with one of same crop need more tests to to evaluate theallelopathic function to grape.