• Korean journal of applied entomology
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• v.34 no.4
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• pp.321-327
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• 1995

This study was conducted to determine the winter ecology of the small brown planthopper (SBPH), laodelphax striatellus Fallen, in Milyang, east Kyungsangnamdo province. The age distribution in the overwintering SBPH population varied according to collection dates. In early December, the population distribution was 60% 4th instar, 30% 3rd instar, 6% 5th instar, 3.4% 2nd instar with very few adults and 1st instar. In early March 5th instars had the highest propotion (47-50%) with 4th instar 44-46%. In early April the adult population was 75-81% of the population. The averaged nymphal instar converted the age distribution of he overwintering SBPH in to the into the numerical values tended to increase continuously. However, there were some differences in the averaged nymphal instar of overwintering SBPH annually and these differences resulted from different age distribution of the overwintering SBPH due to different annual temperature fluctuations during overwitering periods. The weight of the overwintering SBPH increased continuously during overwintering periods. The collection density of the overwintering SBPH population was significantly higher on the levee than in the barley field. Percent nymphal parasitism by haplogonatopus atratus in the overwintering SBPH population averaged about 21% regardless of overwintering years.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.116-118
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• 1984

This study was carried out to know the percentage of parasitism and host preference of Haplogonatopus atratus (Dryinidae) in the nymphs of small brown planthopper. The percentages of parasitism in the nymphal stage of planthopper at each generation were $19.2\%$ for overwinterd generation, $10.8\%$ for the 1st generation on barley field and $21.5\%$ for the 2nd generation on paddy field, respectively. The percents of the parasitism for the respective instars were $78.2\%$(3rd), $17.5\%$(End), and $4.2\%$(4th) when various developmental stages of the planthopper had been caged together. No parasitized individual was found for the instars of the 1st, the 5th and the adult.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.497-501
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• 2014

The small brown planthopper, Laodelphax striatellus (Fall$\acute{e}$n) (SBPH) is one of the important rice pests in Korea, which transmits rice stripe virus (RSV) to rice. This pest is an indigenous species in Korea and has also known to migrate from China to the western coastal areas of Korea. This study was conducted to investigate the wing morphs of SBPH and its parasitism rate of Haplogonatopus atratus Esaki et Hashimoto in Korea. In 2014, SBPH were collected in April and July from 16 sites throughout South Korea and their wing morphs and parasitism rates were measured under the microscope. Percentage of brachypterous male in July was significantly declined compared to that in April, while that of brachypterous female did not change. A positive relationship was found between latitude and percentage of brachypterous adults in April. Parasitism rate of both nymphs and adults were higher in April than July. In addition, nymphal parasitism rate was generally higher in western coastal areas.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.165-169
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• 1990

A study was carried out to investigate some biological characteristics of Pseudogonatopus nudas, a nymphal parasitoid of the whitebacked planthopper (WBPH) under laboratory conditions (26-$28^{\circ}C$). Developmental periods of eggs, larva, prepupa and pupa were 2.5, 7.8, 2.7, and 14.2 days in average, respectively. Total developmental period from egg to adult emergence was average of 27.2 days. More than 83.5% of the wasps emerged in the morning between 6 and 10 o'clock, while very few emerged in the afternoon. The average longevity of female and male were 11.8 and 3.4 days when honey and WBPH nymphs were supplied as food. female laid an average of 25.3 eggs and the oviposition period was 5.4 days. The parasitoid seemed to prefer the 3rd instar nymphas as the host for oviposition with 68.8%, followed by the 2nd (19.6%), 4th (11.05) and 5th instar (0.6%). And no parasitism was recorded from the 1st instar nymphs and in adults.