The Synedrella nodiflora extracts had high biology activity to Pieris rapae. Antifeedant efficiencies of 1% methanol e xtract were 92.22% and 90.0% at 24h and 48h afte r feeding respectively. For the 4th instar larvae，AFC50 and AFC 90 of the extracts were 623.18μg·mL~(-1)，1206.29μg·mL~(-1) at 24h，and were 2454.99μg·mL~(-1) and 2988.27μg·mL~(-1) at 48h after feeding. For the 5th instar larvae，AFC50 and AFC90 were 5277.59μg·mL~(-1) and 7923.24μg·mL~(-1) at 24h ，and 10651.89μg·mL~(-1) and 12584.31μg·m L~(-1...
A rapid Testing method of organophosphorus pesticides residue in vegetables was introduced in this paper. The experimental evaluation was done by means of degree of accuracy，precision and sensitivity，and by compa ring with gas chromato-graphy method which is standard method of our countr y.The results showed that the rate of recovery for this method was over 70% ，the comparatively standard variance was less than 4%，and the lowest d etection limit was 0.02～0.5mg·kg~(-1). All of these show that this kind o...
Toxicity test and field control of Avermectin + Beta- cypermethrin against Plutella xylostella were conducted. The results i ndicated that this compound pesticide showed high level activity to P.xylostella， the LC_(50) was 0.59mg·L~(-1) and cotoxicity c oefficient was 142.14. In pot test，the control efficiency was over 85% and residual activity lasted 10 days at concentration of 5mg·L~(-1) . In the field，the control efficiency was about 95% and residual activi ty lasted 10-15 days as this pesticide was dil...
A regression equation of cucumber yield related to N f ertilizer，plant density was set up by using the D-saturated optimatation desig n method. The optimum combination to get yield 67.5t·hm~(-2) by comp uter simulating is N 390.9～627.9kg·hm~(-2) density of 50925 ～57915 plants per hectare.
The experiment results indicated that the brown blotch y ripening of tomato was closed related to the application of K element. Whichev er stage K deficiency，the incidence and integrated index of tomato brown blotch g ripening were increased. Moreover，the longer K deficiency period，the worse r esults were obtained. Especially at fruit setting to harvesting stage the e ffects of K deficiency increased significantly. In the growing period, K ferti lizer deficiency can affect the yield too.
Jinyou No.4 is a new cucumber F1 hybrid with toleran ce to heat，high resistance to downy mildew，powdery mildew and Fusarium wilt. I t is suitable for open cultivation from spring to autumn. Its plant grows vigoro usly，and it yields 75t·hm~(-2) in spring. Average fruit is about 30 cm length and 180g weight. Fruits are dark green，sweet and crispy，wit h white spine and have good quality and high marketable percentage.
Baixuegongzhu’is a new cauliflower F1 hybrid deve loped by crossing two self-incompatible lines 9346 and 9347. It grows vigorous ly. Its curd is high round with white，tight and good quality. The curd can be h arvested about 60 days in spring and about 85 days in autumn after transplanting . The average yield is 30t·hm~(-2) in spring and 45t·hm ~(-2) in autumn.
Xiabai 45 is a new Chinese Cabbage F1 hybrid by cro ssing self-incompatible line 87-3-1 and 90-7-5. It has early maturity，dise ase resistance and high yield. The yield is about 45～60t·hm~(-2)，3 0% higher than Xiayang 50. It is suitable to be grown in Hebei，Shandong ，Shanxi and Henan.
Jiangshu No.4’ is a new hot-pepper F1 hybrid dev eloped by crossing inbred 0736 with inbred 0517. It has early maturity，good qua lity，and good marketable characters. Its early yield is 15.96t·hm- 2 and total yield is 40.5t·hm~(-2). It is resistance to TMV and An thracnose，and suitable for protected cultivation.
Chengqie No.1’is a new eggplant F1 hybrid. It is early maturity and resistance to disease, The fruit is ellipse with purple lust re. The average fruit weight is about 391g. It is suitable for open cul tivation in north China.
