• Korean journal of applied entomology
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• v.49 no.2
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• pp.139-144
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• 2010

This study investigated the efficiency of mating disrupters for the control of Grapholita molesta(Busck) and Adoxophyes orana in pear orchards. G. molesta was shown 4 peak occurrence, which were different according to treatments. In conventional control, many moths were captured in mid and late April and peaks occurred in mid June, August, and early-mid September. In the non-control treatment, there were low populations in April. A. orana also appeared to 4 peak in 2007. Moths were rarely captured in mating disrupter treatment but many were captured in both the non-control and in conventional treatment. A. orana damage differed significantly between mating disrupter use and conventional control in 2006. Especially, the difference was significant between conventional control and mating disrupter to leaf damage in August, and there were similar results in the damage by G. molesta in the shoots and fruits.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.85-92
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• 1986

This study was conducted to investigate host plant, bionomics, and damage on Bamboo Leaf Rollers in Chonnam area. Species of the leaf rollers attacking the bamboo trees in Chonnam area were Microstega jessica (Butler) and Sinibotys evenoralis (Walker). Among these species, M. jessica (B.) and S. evenoralis (W.) were observed in Damyang but S. evenoralis (W.) alone was found in Naju and Hwasoon. Among the 4 host plant species observed, Phyllostachys nigra var. henonis S., and P. nigra M. were first recorded as host plants of M. jessica (B.), and P. nigra var. henonis (S.) as host plant of S. evenoralis (W.). The occurrence of the M. jessica (B). was once a year with the peak about late May, whereas the occurrence of S. evenoralis (W.) was 2 times a year and the peaks were early June and mid-July, respectively. The average periods of each stage of M. jessica (B.) were 8 days for egg, 293 days for larva, 16 days for pupa, and the longevity of the adult was 12 days for females and 9 days for males. The average periods of each stage of S. evenoralis (W.) were in 1st generation, 11 days for egg, 28 days for larva, 12 days for pupa, and the longevity of the adults was 18 days for females and 15 days for males; and 2nd generation was 7 days for egg, 261 days for larva, 20 days for pupa, and the longevity of the adults was 11 days for females and 10 days for males. The time of most adult emergence of M. jessica (B.) was from 6 p.m. to 4 a.m. and the peak was 8 p.m. to 10 p.m. M. jessica (B,) overwintered as 6th instals in Bamboo shoot sheath but S. evenoralis (W.) overwintered as $1st{\sim}2nd$ instals on the tree leaves of Bamboo. The percentage of damaged leaves with different heights of Bamboo trees were 67.1% at upper portion, 19.0% at middle portion, 14.0% at lower portion. The percentage of damaged loaves with different Bamboo species was 57.0% on P. nigra var. henonis S., 36.5% on P. bambusoides S. et Z., 14.5% on P. pubescens M.. It was showed highly significant negative correlation between percentage of damaged bamboo leaves an tree growth stages.($r=-0.739^{**}$)

• Research in Plant Disease
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• v.10 no.4
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• pp.279-284
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• 2004

A rust fungus has caused a serious early defoliation of Zanthoxylum schinifolium during growing seasons every year at the plantations located at Hadong and Jinju, Kyeongsangnam-Do in Korea. In order to identify the rust fungus and clarify its life cycle in Korea, aeciospores from Pinus thunbergii were artificially inoculated on the leaves of Z. schinifolium. Uredinial stage was successively formed on the leaves of Z. schinifolium. Based on the artificial inoculation test and on the morphological features of the dried specimens collected from P. thunbergii and Z. schinifolium, this rust fungus was identified as Coleosporium xanthoxyli. Morphological features of aecial and uredinial stages of the species were described. The first symptom of the infection was developed from later June to early July. And leaf infection ratio was 17.8%-58.7% during August at Hadong and Jinju regions of Kyeongsangnam-Do in Korea.

• Journal of Korean Society of Forest Science
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• v.76 no.3
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• pp.230-240
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• 1987

Half-sib seedlings of Ginkgo biloba (one-year-old) were treated with various simulated acid rains(pH2.0, pH3.0, pH4.0 and pH5.0) to examine the effects of acid rain on leaf surface area, leaf injury, leaf chlorophyll content and photosynthetic ability of the leaf tissue. The seedlings were grown in a pot($4500cm^3$) containing one of three different soils(nurseryy soil, mixed soil and sandy soil). Simulated acid rain was made by diluting sulfuric and nitric acid solution($H_2SO_4:HNO_3=3:1$, V/V) with tap water and tap water(pH6.4), and treated by 5mm each time for three minutes during the growing seasons(April to October 1985). Acid rain treatments were done three times per week to potted seedlings by spraying the solutions. The results obtained in this study were as follows : 1. Leaf surface area per seedling at pH2.0 level was the lowest among the levels of pH, but those at other pH levels were not significantly different. 2. Leaf injury(injured leaf rate and injured leaf area) increased with decreasing pH levels of acid rain. 3. Leaf chlorophyll content measured during the period June through October was significantly different among the soil types, and that of the seedling in nursery soil was the highest. The lower pH levels of simulated acid rain was treated ; more leaf chlorophyll content was measured at the beginning of treatment, and the more it severely decreased at the late growing period. 4. Photosyntetic abilities, and the highest value was shown in nursery soil. Significand difference in photosynthetic ability among the levels of pH was observed only in August. Photosynthetic ability increased with decreasing pH levels at the beginning of treatment, but decreased rapidly after July.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.239-244
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• 1987

This studies was carried out to find the effect of inorganic matters of Apple Leaves on the occurrence of Alternaria leaf spot and calicium compounds on mycelial growth of Alternaria mali. Diseased leaf rate of Alternaria leaf spot of susceptible apple varieties was 84.8%, moderate resistant 8.1% and resistant 0.3% respectively and in No. of lesion per leaf, the tendency was same. CaO contents of apple leaves was contained much in the resistant varieties than susceptible one. It was estimated that calcium is one of factors on resistance to apple leaf spot by the results of relations among CaO contents and diseased leaf rate from July to August and No. of lesion per leaf was correlated significantly as r=-0.551, r=-0.585, -0.485 but in T-N, $P_2O_5,\;K_2O,\;MgO,\;Na_2O$, there was no difference among varieties. Then, growth of Alternaria mali was possible in the media of which pH ranged up to $11{\sim}13$, and calcium has effect of inhibition on growth of Alternaria mali.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.85-90
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• 1998

A series of experiments were carried out to determine the effect of seed dressing application of chemicals on the early occurring rice insect pests. The number of small brown planthopper adults per 3hills in seed-dressing plot of Imidacloprid WS (Im WS) was 1.6 and its control efficacy was over 90%, compared with that of untreated plot. Rice water weevil was observed in the density of 8.8 larvae per 5 hills seed-dressed Im WS plots(showing 95.5% of control efficacy). Control efficacy of Im WS and Im GR against adult weevils lasted for 26 days after treatment and was higher than that of Carbofuran GR. Rates of injured stems by rice stem maggot and injured leaves by rice leaf miner were 3% and 3.7% in Im WS treatment plot respectively. Seed germination rate after seed dressing with recommended dosage (3 g/seed kg) of Im WS was 71 % on the 1st day and increased on 5th day up to that of untreated seed. The residual amount of Im in seed dressing plot was 0.11 ppm in rice roots and 0.05 ppm in leaves on the 40th day after treatment. Residual effect of Im WSI sustained for 50 days with over 95% insecticidal effect for the rice water weevil and over 90% for the brown planthopper. Quantity of the chemical applied in the field was calculated as 0.084 kg a.i./ha in seed dressing and 0.3 kg a.i./ha in seed box treatment, respectively It took 1 hour to treat insecticide by seed dressing, 2.5 hours by seed box applying, and 3.6 hours by water surface releasing per 990 $m^2$.

• Korean Journal of Organic Agriculture
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• v.14 no.3
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• pp.315-323
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• 2006

The potential of the predatory mite Phytoseiulus persimilis (Acarina : Phytoseiidae) to control two spotted spider mite Tetranychus urticae (Acarina : Tetranychidae) was investigated on sustainable strawberry fields in Jeonnam area. The density of T. urticae increased from 4th and 7th weeks after single and two timings release P. persimilis, respectively. On the three timings of release plot, number(density) of T. urticae on a leaf maintained fewer than 10 during the 15 weeks after release. In the 1,000 release of P. persimilis per $100m^2$ plot, P. persimilis could not suppress T. urticae. In the 2,000 release plot, P. persimilis could suppress T. urticae with low density which was the similar in the 3,000 release plot. Two-spotted spider mite, T. urticae, occurred from late March and increased density in Hampyeong area. In the P. persimilis released field, T. urticae inhibited continuously after release. In Boseong area, density of P. persimilis increased 50 per 10 leaves through increasing of T. urticae. Percent of occurrence of T. urticae showed high $10.5{\sim}75.5%$ in none-release predatory mite but not high in release treatment. T. urticae on sustainable strawberry field could be inhibited by P. persimilis.

• Research in Plant Disease
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• v.17 no.3
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• pp.311-316
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• 2011

Pepper powdery mildew causes increasingly economical damage due to increased cultivation of pepper in greenhouses. To assess resistance of pepper resources against pepper powdery mildew, we developed a novel evaluation formula for pepper resistance against powdery mildew. The evaluation formula named S index is as follows; (number of the highest disease leaf/top leaf number)-(number of the lowest disease leaf/top leaf number). Positive correlation (81%, P = 0.01) between S index and authentic disease leaf rate was observed from the pepper plants infected by powdery mildew. Various pepper species from our genetic resources were evaluated to identify pepper varieties conferring resistance against powdery mild using S-index. Capsicum frutescens accessions 3CA131 and C. baccatum accessions 3CA0162, 3CA174, 3CA176 showed high resistance to powdery mildew, but none of C. annuum was resistant. Results suggest that S-index proposed in this study is useful to assess resistance evaluation of powdery mildew in chili pepper breeding.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.138-141
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• 1982

The insecticides aldicarb$(Temik^{(R)}\;15G)$, carbofuran$(Curaterr^{(R)}\;3G)$, and disulfoton$(Disyston^{(R)}\;5G)$ were evaluated in the field for the control of the pine gall midges(Thecodiplosis joponensis Uchida et Inouye) at rate of 5 a.i.g/cm dbh using the method of circle-furrow treatment(ca. loom in furrow depth), apart 50cm Iron the trunk of the pine trees. In addition, for improving the application method of granular insecticides the effects of conventional circle-furrow treatment were compared with those of pit treatments and radical-furrow treatments. A single root-zone treatment of aldicarb and carbofuran i the pine trees was significanlty effective for the pressure of the gall incidence by the insects. Control effectiveness in three-pit treatment was identical with those in conventional circle-furrow treatment. The pit treatment compared with the circle-furrow and radical furrow treatments would be a further feasible method in saving labor cost.