Search

Plant-parasitic nematodes on potato were identified by morphology of juveniles and adults. Extraction of vermiform nematodes in soil and roots was made by modified Baermann technique and root gall index was dertermined following Bridge and Page (1980) chart. Results show that there were six genus, five families and one order of parasitic-plant nematodes in soil. The ratio of Helicotylenchus was the highest (93.33%), followed by Meloidogyne (83.33%), Pratylenchus (50%), Criconemella (33.33%), Ditylenchus (30%), and Globodera at only 20%. Density of plant parasitic nematodes ranged from 500 individuals to 3,000 individuals per 50 cm3 of soil, 200 to 2,204 individuals per 5 grams of roots. Root gall index ranged from 1,754 to 5,262.

Root-knot nematodes (Meloidogyne sp.) are an important plant – parasitic group on green lollo lettuce. Experiments, included solarizion, bio-fumigation, burning and keep drying soil were carried out to control root-knot nematodes on lettuces in Lamdong province. The results showed that burning method was the most effective (in soil) with only 28 juveniles/100g of soil and 96.75% after treating compared to the control with 1312 nematodes/100g of soil. The infection proportion of root-knot nematodes (1.433) and the number of juveniles of root-knot nematodes (201 juveniles/5g of root) in the burning were the lowest. Therefore, the height and the yield of crop treated with this method were the highest, proved by 25.99 cm and 30.25 tons/ha, respectively. In contrast, the root infection proportion in the control was the highest, accounting for 5.733 while the figures for the height (18.8 cm) and the yield of crop (15.93 tons/ha) were the lowest.

Huyện Đức Trọng có điều kiên tự nhiên và đất đai phù hợp đề phát triển cây dứa cayenne. Các thí nghiệm được tiến hành trên các loại phân bón phosphate chậm tan bao gồm apatit Lào Cai, Gafsa, Ferphos, Roc-3 để duy trì chất lượng đất trồng cây dứa trong ba năm. Phối hợp kali chlorua và amonium sulfate với phân bón phosphate để nhằm đánh giá năng lực của pH, RC, phốt pho, kali và biến đổi nitơ trên đất. Kết quả cho thấy pH và EC giảm dần, tổng số và hàm lượng nitơ hòa tan tăng nhẹ, hàng lượng kali giảm dần hàng năm, hàm lượng photpho được duy trì ổn định trong các thí nghiệm GAF, APA, TSP.