| 1. Identification pathogen of tomato root-knot nematodeThe tomato diseased samples were collected from protected fields in nine cities ofGansu province infested with root-knot nematode. There were a large number of femaleswithin root. The morphological characters of males, females, the juvenile2, their eggs andthe perineal pattern of female were observed and measured. Meanwhile, UsingrDNA-ITS-PCR method to identify the samples, the results showed that the ITS sequenceof11root-knot nematode populations and known Meloidogyne incognita species fromGenBank database almost had homoeology, which reached99%. Its sequence length wereabout690-695bp. All samples of root-knot nematode belonged to M.incognita.2. Identification physiological races of M.incognitaPhysiological races of M.incognita were identificated with differential hosts ofInternational Meloidogyne Project. These hosts were tobacco (NC95), cotton(Deltapine16),pepper(California wonder), watermelon(Charleston Gray), peanut(Flordrunner) and tomato(Rutgers).11M.incognita populations, among which9populations were race1, and1populations were race2and1populations were race3. Dominant physiological race ofM.incognita was race1.3. Chemotaxis of different salts on M. incognita J2The chemotactic responses of M. incognita were studied in salt gradients created in anagarose gel. Chemotaxis effect of M. incognita induced by37inorganic salts and11organic salts were tested on agrose plate. M. incognita was repellented to salts thatincluded Cl-and SCN-. Other salts that comprised the same anions had differentchemotactic responses, among which M. incognita was repellented to ammonium salts thatincluded Ba(NO3)2, NH4NO3, Mn(NO3)2, and hydrogen-phosphate salts that includedKH2PO4, K2HPO4, and bicarbonate salts that included Na2CO3, K2CO3,(NH4)2CO3,KHCO3, and hydroxyl salts that included KOH and NaOH, and organic acid that includedC2H4O2, C3H6O3and C4H6O6. No difference was observed in the repellent or attractionproperties of different salts. The effect of repellence was arranged as SCN-﹥NO3-﹥Cl-﹥OH-﹥CO32-﹥H2PO4-﹥organic acid﹥SO42-.A significantly positive relationship was observed in the chemotaxis of nematodesand concentration of KCl, Ba(NO3)2, NH4NO3,Mn(NO3)2,(NH4)2CO3, C2H4O2and C4H6O6, while the concentration of other salts testeddid not influence nematode chemotaxis significantly.4. Mortality of different salts on M. incognita J2The effects of fourteen kinds of inorganic salts and organic salts with four differentconcentrations on mobility of the second stage juvenile of M.incognita were tested in sandcolumn. The results showed that all of salts had a strong inhibition mortality to J2. The J2mortality distance was significantly decreased with the increase of treatingconcentrations.Compared with the control, salts including BaNO3, K2HPO4, CsCl andKSCN had the strongest inhibition mortality to J2.The mortality distance in the treatmentby0.5,1,2,4μg/mL BaNO3for15d were0.90cm,0.88cm,0.78cm and0.69cm,respectively. At the same concentration, the mortality distances in the treatment byK2HPO4were0.91cm,0.64cm,0.85cm and0.53cm, respectively. And the mortalitydistance in the treatment by CsCl were0.93cm,0.71cm,0.77cm,0.62cm, respectively.And the mortality distance in the treatment by KSCN were0.92cm,0.84cm,0.74cm and0cm, respectively. The concentration of other salts tested did not influence nematodemortality significantly.5. Infectivity of different salts on M. incognita J2The effects of different inorganic salts and organic salts with different concentrationson infectivity of the second stage juvenile of M.incognita were tested in the laboratory. Theresults showed that all of salts had a strong inhibition infectivity to J2. The J2infectivityrate was significantly decreased with the increase of treating concentrations. The J2infectivity rate in the treatment by2μg/mL salt demonstrated the lowest, while theinfection rate was24%in the control. These salts had the best infectivity effect for M.incognita J2, such as NH4NO3, KH2PO4, K2HPO4,(NH4)2CO3, CsCl, NaSCN,(NH4)2SO4,and tartaric acid. |
