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Although Heterodera trifolii is commonly known as the clover cyst nematode, recently the nematode has been identified as a serious menace for Chinese cabbage growers in highland areas in Korea. Soil samples were collected from two Chinese cabbage fields highly infested with H. trifolii in highland areas of Korea, Jungsun and Samcheok, in 2014 and 2015, respectively. A total of 777 (2 × 2 m sampling area) and 414 (5 × 5 m area) soil samples were collected from Jungsun and Samcheok, respectively. The total cysts, cysts with eggs, number of eggs, and empty cysts were calculated for each sample. Distribution patterns for these variables were characterized using spatial analysis by distance indices (SADIE) and variogram model analysis. The aggregation index for cysts with eggs was higher in Jungsun (89.32) than Samcheok (3.63), which indicated that the cyst population density was higher. However, the spatial association of total cysts versus cysts with eggs was higher in Samcheok. The Gaussian model showed reasonable independent range of the nematode in Jungsun and Samcheok to be approximately 53.66 m and 48.54 m, respectively. The model suggested that each nematode sample should be taken at least 50 m apart in the given areas. Inclusion of this distribution pattern may significantly minimize the number of samples in future sampling methods, which could save time and labor, and initiate management practices by elucidating spatial variability factors that influence crop yield.

Heterodera schachtii is a well-known, destructive pathogen of Chinese cabbage (Brassica rapa pekinensis) in Korea, and several studies have attempted to find a potential control measure against it. This study is the first to investigate the effects of varying temperature on the reproduction and damage potential of H. schachtii to Chinese cabbage. Chinese cabbage plants were inoculated with H. schachtii at different densities (1, 2, or 4 juveniles per gram of soil) and grown under three temperature regimes: constant (15, 20, or 25 °C), increasing (10, 14, and 18 °C), and fluctuating (positive, 16.7–22.0 °C; negative, 21.5–11.5 °C). At a constant temperature after 30 days of inoculation, both Chinese cabbage and H. schachtii performed best at 20 °C. However, after 60 days of inoculation, H. schachtii had a significantly higher population at 20 °C, whereas cabbage growth was best at 25 °C. With increasing temperature, the numbers of cysts and females did not change significantly, and reached maxima at an initial temperature of 14 °C. However, the number of leaves and weights of the Chinese cabbage plants significantly differed at 14 °C. Under fluctuating temperatures, temperature decreases reduced the H. schachtii population.

The robber fly, Promachus yesonicus, a predator of scarab adults and larvaewas observed on golf clubs in Korea to determine its seasonal activity, daily activity, and relationship to scarab adult activity. P. yesonicus adult density varied more than 10-fold among the four golf clubs where it was observed, with the most activity being at golf clubs with the most scarab adults in June and July. At Yongwon Golf Club P. yesonicus activity closely tracked Popillia quadriguttata activity and both peaked in late June and early July. The ratio of scarab adults (mostly P. quadriguttata):P. yesonicus adults was 8:1. On average mean of 7.5% of all P. yesonicus adults observed in visual surveyswere holding captured prey. 50% of all captured preywas a scarab turf pest, P. quadriguttata. At Yongwon Golf Club, regression analysis indicates that P. quadriguttata activity explains 75% of the variation in activity of P. yesonicus. The potential impact of P. yesonicus on populations of P. quadriguttata and other scarab turf pests is discussed.

Life history and temporal distribution of Ectinohoplia rufipes larvae (Coleoptera: Scarabaeidae; Melolonthinae) were studied on multiple courses at two Korean golf clubs in Gapyeong and Anseong, Gyeonggi Provinces. Larval density of E. rufipes was higher in roughs than fairways and higher on older courses than on newly constructed ones at each club. Larval density of E. rufipes in fall reached three to four times compared with the previous year in five or six year old courses in the first opened courses, but that took two or three years to reach three to four times in the newly constructed courses in the same golf club. Monthly sampling showed that larvae were distributed 3.0 to 5.8 cm beneath the soil surface; mean larval density ranged from 0.2 to 1.2/m 2 at each club. Most larvae overwintered as third instars that pupated in early May. Adults were first observed in late May at each course. Adults were first seen in emergence cages installed over a grub-infested portion of rough in early June. Eggs were deposited from late June to early July. Eggs hatched in mid to late July and larvae developed to become third instars by early October. Implications of these findings for managing E. rufipes on Korean golf courses are discussed.

Black pine bast scale, Matsucoccus thunbergianae, is one of the most destructive pests of black pine trees throughout Korea. Toxicities of five commercially available insecticides for scale insects were compared in the laboratory with that of buprofezin 40SC, which is currently used to treat the disease in Korea. Fenitrothion 50EC and buprofezin 40SC significantly suppressed the adult emergence of intermediated male nymphs when exposed to the recommended-field concentrations (RFCs) of 500 and 4,000 ppm, respectively. Fenitrothion 50EC was effective against male pupae even at one-fifth of the RFC, and showed no significant difference from buprofezin 40SC. Fenitrothion 50EC caused significantly higher mortality than buprofezin 40SC towards intermediate female nymphs and eggs, even at half RFC, and on female adults at one-tenth of its RFC. In a field test in a black pine arboretum, 50 ppm of fenitrothion 50EC was equally effective to its RFC (500 ppm) on the settled crawlers. Toxicities of fenitrothion 50EC and buprofezin 40SC to humans, other mammals, and non-target organisms are discussed. Fenitrothion 50EC can be used for urgent control of M. thunbergianae in limited outbreak areas at lower concentrations than its RFC.

Out of some isolated Heterorhabditis bacteriophora from Korea, ecological study on two isolates which had different geographical features was investigated. That is, effects of temperature and dose on the pathogenicity and reproduction of two Korean isolates of H. bacteriophora were investigated using Galleria mellonella larvae in the laboratory. The median lethal dose (LD50) decreased with increasing temperature, but increased at 35 °C. The optimal temperatures for infection were 30 °C for H. bacteriophora Jeju strain and 24 °C for H. bacteriophora Hamyang strain. The median lethal time, LT50 of H. bacteriophora Hamyang strain was recorded at 13 °C to 35 °C and that of H. bacteriophora Jeju strain was recorded at 18 °C to 30 °C. The number of established nematodes in G. mellonella larvae was significantly different depending on temperature and dose. When G. mellonella larvae were exposed to 300 infective juveniles (IJs), mortality of G. mellonella gradually increased with exposure time with H. bacteriophora Jeju strain but not with H. bacteriophora Hamyang strain. 87.5% mortality of G. mellonella was recorded by H. bacteriophora Hamyang strain after 1440 min whereas 100% mortality was recorded by H. bacteriophora Jeju strain after 4320 min. The time from infection to the first emergence of nematodes decreased with increasing temperature. Duration of emergence of the two strains in the White traps also decreased with increasing temperature. The highest progeny numbers of H. bacteriophora Jeju strain were 264,602 while those of H. bacteriophora Hamyang strain were 275,744 at the rate of 160 IJs at 24 °C.

Twenty-seven different samples that included various plant components (leaves, fruits, and stems) were collected from 21 tree and herbal species in 19 genera from Gezira locality, Sudan. Methanol or hexane extracts of the 27 samples were screened for nematicidal activity against second-stage juveniles of Meloidogyne incognita in the laboratory. The juveniles were exposed to 500 ppm of each plant extract for 24, 48 and 72 h. Five plant extracts exhibited highly promising mortality rates of 95–99% after 72 h of exposure, which were statistically different from the other extracts. These extracts were from Dinbera retroflexa (leaves), Cucumis melo var. agrestis (fruits), Eucalyptus microtheca (leaves), Acacia nilotica (pods), and Chenopodium album (leaves). Six extracts derived from the leaves of Solenostemma argel, Aristolochia bracteolate, and Ziziphus spina-christi and the seeds of Aregimone mexicana, Datura stramonium, and Azadirachta indica produced relatively high mortality rates of 94–80% after 72 h of exposure. The 5 most nematicidal plant extracts listed above were further screened against similar stage juveniles of the nematode species using only 50 ppm for 24, 48, and 72 h. Three plant extracts, C. melo var agrestis (fruits), A. nilotica (fruits), and C. album (leaves), exhibited 41, 42 and 45% mortality rates, respectively. The mortality rate increased with increasing exposure time for most of the extracts.

Korean entomopathogenic nematodes (EPN), Steinernema carpocapsae Pocheon strain, Steinernema sp. GSNUS-4 strain, Steinernema sp. GSNUS-14 strain, Steinernema sp. GSNUS-16 strain, Heterorhabditis sp. GSNUH-2 strain, and Heterorhabditis sp. GSNUH-3 strain were evaluated for the biological control of pellucid zygaenid, Pryeria sinica Moore (Lepidoptera: Zygaenidae), a leaf-feeding insect pest of Euonymus japonica Thunberg. In addition, persistence of S. carpocapsae Pocheon strain on E. japonica foliage was checked. Nematode species, strain, and concentration influenced infectivity of Korean EPNs against 3rd instar of P. sinica larvae. S. carpocapsae Pocheon strain was the most effective nematode. Larval mortality by S. carpocapsae Pocheon strain in the exposure experiments was low in both light and dark conditions representing 36.7% at 100 infective juveniles/larva in each dark and light condition. Mortality by fenitrothion, however, was 100% 3 days later. Infectivity of S. carpocapsae Pocheon strain was not different between non-exposed foliage and exposed foliage to sunlight for 30 min. Mortality of 4th instar of P. sinica larvae was very low for both S. carpocapsae Pocheon alone and S carpocapsae Pocheon with spreading agent. Application time of nematodes, shading, and leaf position on the tree influenced persistence of S. carpocapsae Pocheon strain on E. japonica foliage. Nematode survival on foliage was positively correlated with shading level and higher at the lowest level than the middle or upper level of the tree.

A study was done on the taxonomy and morphology of plant parasitic nematodes (Tylenchida) found in a Guneid sugarcane factory field of Saccharum officinarum (sugarcane), in Gezira state, Sudan. The samples were collected from around the root zone of sugarcane stools at a depth of 10 to 15 cm. One new species belonging to Hoplolaimidae was identified and studied. Helicotylenchus zeidani sp. nov. is characterized by a smooth head and a conical tail with a projection. It is 0.72 mm (0.62 to 0.81 mm) long, a = 32.4 (25.6 to 36.6), c = 36.9 (29.2 to 53.1) with a medium sized body and shorter stylet.

Nine herbal powders were tested against root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood (Tylenchida: Meloidogynidae) under greenhouse conditions. The herbal powders were collected from Gezira State, Sudan. Herbal powders were used without extraction to simplify the application by farmers. Most of the herbal powders were effective in controlling M. incognita in the soil compared to the control. Some treatments (e.g., Acacia nilotica (L.), Argemone mexicana L., and Azadirachta indica A. Juss) had statistically lower Root Knot Index (RNI) than the control. The number of juveniles per 100 g soil was lower in soil amended with Dinbera retroflexa (Vahl), Azadirachta indica , Salvadora persica (L . ), and Acacia nilotica than in unamended soil. The results of both RNI and number of juveniles were not significantly different from the synthetic nematicide used. Herbal powders from A . indica and Acacia nilotica may be promising in controlling of this pest because they are readily available to farmers in tropical regions.

In previous laboratory studies, entomopathogenic nematodes andBacillus thuringiensissubspeciesjaponensis(Btj) caused additive or synergistic mortality in third-instarCyclocephala(Coleoptera: Scarabaeidae) grubs when the nematodes were applied at least 7 days afterBtj.This type of mortality was observed forC. hirta,a species that is not very susceptible toBtj,and forC. pasadenae,a species that has intermediate susceptibility toBtj.In the present study, this observation was confirmed for third-instarAnomala orientalis,a species that is highly susceptible toBtj.In greenhouse and field studies, additive or synergistic interactions between nematodes andBtjwere observed for all three scarab species. The interactions were variable, and to achieve acceptable grub control, high concentrations ofBtjhad to be applied. A subsequent greenhouse experiment showed that young third-instarC. pasadenaewere more susceptible toBtjthan older third instars. In addition the interaction between nematodes andBtjwas also more synergistic in the younger than in the older third instars. In a field test against a population ofC. hirtaconsisting of late second and early third instars, combinations of nematodes andBtjat economic application rates provided acceptable control levels whether applied simultaneously or with a 4-day delay betweenBtjand nematode application. Our observations suggest that curative control of white grubs is possible with combinations of entomopathogenic nematodes andBtjif the applications are done when populations consist of second and early third instars.