This study was estimated for cabbage aphid, Brevicoryne brassicae in Brassica campestris L. var. rapa (L.) Hartm. in order to institute of Economic injury levels(EILs). B. brassicae was innoculated on April 29, in differently 0, 5, 10, 20 and 40 adults per ten plant, respectively. After inoculated of B. brassicae, the density was increased until harvest ing gradually in all plots except non innoculate plot. and Higher inoculation density were increased higher than lower inoculation density. Percentage of damage leaf was higher in plots with higher initial aphid density than in plots with lower initial aphid density. And the leaf weight of commodity were decreased in higher initial aphid density. The decreasing rates of leaf weight of commodity was increased with increasing initial aphid density. The relationship between initial B. brassicae densities and the decreasing rates of leaf weight of commodity was well described by a linear regression, Y=0.8416X-3.5147, R2=0.94. Based on the relationship, the number of adults per 10 plant which can cause 5% loss of yield was estimated to be approximately 10.1. And EILs was estimated to be approximately 1.0 adults/plant in late April.
To control pest of Brassicaceae leafy vegetable(leaf broccoli, Red Mustard Leaf, Tatsoi) which grows at vinyl house in IKSAN, Jeollabuk-do, the non-treatment was set as negative control, and treatment was divided into Parasitic natural treatment group and general treatment group. And incidence density of pest was surveyed and control effect was analyzed. As a result, in case of spring plants, the leaf damage ratio was decreased by 31% in Leaf broccoli, 30% in Red mustard leaf and 27% in Tatsoi compared to untreatment. In case of autumn plants, it was decreased by 32%, 41% and 17% respectively. The key pests were Plutella xylostella, Pieris rapae, Myus persicae Sulzer, Thrips palmi and Striped cabbage flea-beetle. Compared with the untreatment, the incidence density of each was significantly controlled. Other pests include Spodoptera exigua, Macdunnoughia purissima, Macdunnoughia purissima which showed high incidental density sometimes. In case of spring plants, the number by treatment was increased by 117% in Leaf broccoli, 85% in Red mustard leaf and 1,000% in Tatsoi. In autumn plants, it was increased by 132%, 257% and 1,077% respectively. The used Parasitic natural and eco-friendly materials were Cotesia glomerata, lacewing, ladyburg, Orius laevigatus, Encarsia formosa, Entomopathogenic nematode, Chungjigi and Togkaki. During early development of each pest, the Parasitic naturals were grazed 2~3 times at the interval of 7~10days. During the peak time, eco-friendly materials were sprayed 1~2 times. Based on this, comprehensive management model was drafted by period for each Brassicaceae vegetables pest.
To control Thrips tabaci in Korean leek and green onion which grow at vinyl house in IKSAN, Jeollabuk-do, the non-treatment was set as negative control. In general treatment group, 120 mesh gauze was installed on the side window after planting(May, 2nd) and, in spring, Orius strigicollis (1.0/m2) was grazed 3 times every 7 days from mid of May which is early development stage and In the mid of June, which is the peak stage, plant extracts were sprayed one time. In autumn, O. strigicollis was grazed 3 times every 7 days from mid of September which is early development stage, and in the mid of October, which is the peak stage, plant extracts were sprayed one time. The result shows that the leaf damage ratio was decreased by 22% in Korean leek and by 27% in green onion compared to the untreatment. And the control value of Thrips tabaci shows 78.7% in korean leak and 90.6% in green onion. The density control effect of Thrips tabaci was significantly controlled under max 6.2/plant in general treatment group compared max 25/plant in the untreatment and this result was similar in green onion. The yields by general treatment was increased by 85% in Korean leek and 56% in green onion, compared with non-treatment yields, which was 900kg/10a in Korean leek and 1,287kg/10a in green onion.
This study was conducted for establishment of Economic injury levels(EILs) of the tea red spider mite, Tetranychus kanzawai on Rubus coreanus. T. kanzawai was innoculated on May 7 in differently 0, 5, 10, 20 and 40 adults per plant. And pesticide was treated in late April, early May, middle May and late May, respectively.
After inoculated of T. kanzawai, the density was increased until the mid-June and decreased gradually in all plots. And higher inoculation density were increased higher than lower inoculation density. Growth variables were not different among experimental plots except number of fruit set, but the number of fruit set and yields were decreased with increasing initial mite density.
Densities of T. kanzawai on treated time of pesticide was lower in later treatment time than early treatment time. The late April treatments were not effective of pesticide in harvesting season.
The rates of yield loss increased with increasing initial mite density. The relationship between initial T. kanzawai densities and yield losses was well described by a linear regression, Y = 0.6545X + 3.0425, R2=0.9313. Based on the relationship, the number of adults per plant which can cause 5% loss of yield was estimated to be approximately 3.0. And EILs was estimated to be approximately 8.3 adults/leaf in mid-May.