Root-knot nematodes (RKNs) (Meloidogyne spp.) are well known disease problem causing major losses in vegetable crops. Although, chemical nematicides have been used as one of the primary means for controlling RKNs, reliance on these nematicides is associated with heavy costs and negative effects on human health and environment. In this research, the suppressing potential of 6 Iranian commercial fertilizers on RKNs was investigated in laboratory and greenhouse conditions as an alternative to reduce the use of chemical nematicides. For this purpose, M. javanica inoculum was thoroughly mixed with autoclaved sandy loam soil. Then, 6 fertilizers (biofertilizer, phosphate chemical fertilizer (phosphate), potassium chemical fertilizer (potassium), peat moss, vermicompost, and leaf mold) were added individually to the inoculated soil, according to the defined treatments. The nematicide Cadusafos was used as a positive control. A negative control was also included in the experiment (including no fertilizer and no nematicide). Four-leaf seedlings of the tomato (Super Chief cv.) were transferred to the pots filled using 2 kg of the treated soil. After 60 days, reproduction factor (RF), egg mass, and root galling of the nematode were recorded. The results showed that, fertilizer-treated soils had significantly (P≤0.05) lower root galling, egg mass, and RF compared to the negative control. After the nematicide treatment, the highest suppression capability on the RKN was obtained in treatments of phosphate, biofertilizer, potassium, vermicompost, peat moss, and leaf mold, respectively. It can be concluded that, replacing chemical nematicides with fertilizers may be considered as a successful nematode management in tomato fields.

No abstract

No abstract

In this article, the biology and fertility life table parameters of the cabbage aphid, Brevicoryne brassicae (L.) (Hemiptera: Aphididae), were studied on cauliflower leaves, Brassica oleracea var. botrytis (Brassicales: Brassicaceae), of the cultivars Smilla, Snow mystique, White cloud, Buris, Galiblanka, Snow crown, SG, and Tokita. This study was conducted under controlled conditions: 25 ± 2°C, 65 ± 5% relative humidity (RH), and 16:8 (L:D) h photoperiods. Statistical analysis showed that there was a significant difference ( P  < 0.05) between the different growth stages and the mean number of laid nymphs. Further, the maximum and minimum growth periods were observed on Galiblanka and Buris cultivars, respectively. The shortest nymphal instar growth period was observed on the Smilla cultivar (6.70 d), and the longest lifespan was seen on the White cloud (8.10 d). The Smilla cultivar (39%), in an adult emergence stage, and the SG (88%) revealed the lowest and highest rates of survival, respectively. Aphids reared on the Smilla cultivar were found to have increased due to the high intrinsic ( rm ) and finite (λ) rate of increase and the low doubling time (DT). The results indicated that the application of cultivars affecting adult reproductive parameters could be a good solution to cabbage aphid control management.

Summary Root-knot nematodes are among the most important pests that reduce tomato yield in greenhouses and fields in Iran. The scope of this research was to evaluate the antagonistic effect of Trichoderma viride and Pseudomonas fluorescens CHA0 on the reproduction and galling rate of Meloidogyne javanica in tomato roots. A pot experiment was conducted on seedlings of tomato cultivars Bony best, Falat, Mobile and Walter grown in sterilized sandy loam soil. Inocula used for artificial inoculation were 3 J2/g of soil for the nematode, 1×106 spores/ml for the fungus and 1×109 cfu/ml for the bacterium. The nematicide RUGBY® 10 G (cadusafos) was used as a reference product at 2g per each pot. Two months after inoculation, the number of knots and egg masses per root in the treatments were (with descending order): control (nematode), nematode+bacterium, nematode+fungus, nematode+fungus+bacterium and nematode+nematicide. The combination fungus+bacterium enhanced the biocontrol effect against M. javanica activity as compared to the fungus and bacterium stand-alone treatments except for the cases of the cultivars Mobile and Bonny best in which the effect was similar to the one by the fungus alone. The fungus + bacterium combined treatment was equally effective to the nematicide treatment for all cultivars. The highest and lowest rate of nematode activity was observed in Walter and Mobile cultivars, respectively.