STUDIES ON OSCINELLA FRIT LINN.

Data, collected in Sweden during the year 1927, indicate the existence of considerable variation in extent of infestation of the grain of different varieties, sown at the same time. Also they suggest that sterility or "blindness" of grain may be a varietal character.     

THE FRIT FLY AND ALLIED STEM-BORING DIPTERA IN WINTER WHEAT AND HOST GRASSES

Sampling for stem-boring larvae was undertaken in 1954-56 on ley plots of Lolium perenne, Dactylis glomerata, Festuca arundinacea, F. rubra, Agrostis tenuis and Poa pratensis in randomized experiments at Hurley, Berks. The samples showed infestations by dipterous larvae, mainly species of Oscinella, Meromyza and Opomyza. The larvae showed preferences for specific grass hosts. More larvae were found where plots had been grazed throughout the season than where an early hay cut had preceded grazing. The total numbers of larvae varied between o and 688 per sq.yd. in November.
The larval populations of the leys were reflected in the populations in winter wheat which followed the plough-up of the leys. Populations of up to sixty-five larvae per sq.yd., mostly species of Oscinella , were found in the wheat in March. In 1956 a heavy larval infestation was associated with the death of considerable numbers of wheat plants.     

THE EFFECTS OF SPRAY TREATMENTS ON INFESTATION OF THE OAT CROP BY THE FRIT FLY (OSCINELLA FRIT L.)

Criteria are given for the timing and assessment of the effect of sprays on experimental plots, based on biological observations at Silwood Park from 1950 to 1955 and on previous work.
A preliminary experiment on small plots in 1952 indicated that 'blanket spraying' with DDT and parathion throughout the life of the crop gave protection against both tiller and grain attack. A more detailed replicated plot trial in 1953 showed that for oats planted on 22 April two carefully timed tiller sprays with parathion reduced tiller infestation from 31 to 3%. Six panicle sprays at weekly intervals reduced a heavy grain attack of 60% to 13%. Dieldrin was also effective but significantly less so than parathion. Much of the damage to the crop was caused by weed growth following initial loss of the primary oat shoots.
In 1954 and 1955 two and three parathion sprays were applied to 2-acre fields in order to study recolonization. Despite almost complete control of the tiller generation, a normal evenly distributed infestation of the panicles was found.
It is concluded that good control of the tiller generation may best be achieved by a spray programme based on knowledge of the phenology of the fly combined with that of the crop. The first general emergence in early May is likely to be critical.
Reinvasion of a sprayed crop may take place within 4–5 days and panicle infestation may not be causally related to tiller infestation in the same field.     

植物挥发性次生物质在植食性昆虫、寄生植物和昆虫天敌关系中的作用机理

植物挥发性次生物质在植食性昆虫、寄生植物和昆虫天敌关系中的作用机理杜永均,严福顺（中国科学院动物研究所,北京１０００８０）植物挥发性次生物质是一些分子量在１００—２００的有机化学物质,包括烃类、醇类、醛类、酮类、有机酸、内酯、含氮化合物以及有机硫等化...     

EXPERIMENTS ON THE MODE OF ACTION OF DIELDRIN SEED-DRESSINGS AGAINST SEEDLING ATTACK BY THE LARVAL FRIT FLY, OSCINELLA FRIT L

Experiments with dieldrin seed-dressings were done to see whether the conditions favouring their action against wheat bulb fly larvae apply also to frit fly.
Experiments with oats and wheat in boxes and a small field trial with oats showed that fewer newly hatched larvae were killed when dieldrin-treated seed was sown deeply than when sown 1/4 - 1/2 in. deep; shallow sowing probably puts the insecticide where the larvae are likely to meet it before they attack the plant. Kill was never complete even with dieldrin applied at almost forty times more than the highest rate normally used. This is partly because some larvae hatch from eggs on the plant and these, unlike those from soil eggs, can enter the shoot without touching the seed dressing.
Even in the most favourable circumstances (large doses of dieldrin applied to the shallow-sown seed and the plant at the one-leaf stage at the time of attack) there was little evidence that frit fly larvae are killed inside the shoot by systemic action of dieldrin translocated from the seed. This is not because the pales which normally surround the oat seed impair the uptake of insecticide, or because of any other factor specific to oats. Frit fly larvae also survived in wheat from seed dressed with doses of dieldrin that can kill almost all wheat bulb fly larvae by systemic action. Possible reasons for this difference are discussed.     

OSCINELLA FRIT L. IN SOUTH WALES. THE RELATIONSHIP BETWEEN SOWING DATE, PLANT DEVELOPMENT AND PROGRESS OF ATTACK IN SPRING OATS

The degree of lateness of sowing of spring oats in south Wales is reflected in a proportional increase of frit-fly damage to the shoots. Late-sown crops are also more subject to heavy attacks on grain than those sown earlier.
Equations are given relating the development of frit-fly attack both to the growth of the plant and to the date of sowing.     

蚜虫寄主植物与取食部位的多样性

在中国科学院动物研究所已有标本采集记录和国内外文献资料的基础上,分别从蚜虫类Aphidina科级和属级阶元系统研究世界范围内蚜虫寄主植物与取食部位的多样性.蚜虫的寄主植物种类繁多,涉及267科2120属,尤其以菊科、禾本科、豆科、伞形科、唇形科、蔷薇科、茜草科、兰科、壳斗科、杨柳科、胡桃科等植物为主.13科蚜虫的寄主植物差别很大:在科级水平,球蚜科Adelgidae、纩蚜科Mindaridae和平翅绵蚜科Phloeomyzidae的寄主植物类群比较单一,蚜科Aphididae和瘿绵蚜科Pemphigidae的寄主植物范围最为广泛;在属级水平,各属蚜虫间寄主植物也有明显差异,有143属蚜虫的寄主植物多于2科,其中蚜科的属占多数,蚜属Aphis、瘤蚜属Myzus、长管蚜属Macrosiphum、粗额蚜属Aulacorthum和声蚜属Toxoptera的寄主植物最多,各超过100科290属.在不同的寄主植物上寄生着不同种类的蚜虫,其中16科47属寄主植物上寄生的蚜虫多于14属.蚜虫在寄主植物上的取食部位丰富多样,可分为7类,分别为叶片、嫩梢、嫩枝、茎、花、根部、果实等.以叶片、茎、嫩枝和嫩梢为蚜虫主要取食部位.平翅绵蚜科主要取食嫩枝、茎和根部,短痣蚜科Anoeciidae主要取食叶片、嫩梢和根部,球蚜科、群蚜科Thelaxidae和毛管蚜科Greenideidae取食叶片、嫩梢、嫩枝和茎等部位,纩蚜科取食叶片、嫩梢、茎和花等部位,大蚜科Lachnidae和斑蚜科Drepanosiphidae除取食叶片、嫩梢、嫩枝、茎等部位外,前者还在根部取食,后者还寄生在果实上,根瘤蚜科Phylloxeridae在除花以外的其它6个部位取食,蚜科、瘿绵蚜科和毛蚜科Chaitophoridae的取食部位最为多样,它们在上述7个部位均可取食.还初步讨论了在不同寄主植物上蚜虫物种的分化,以及蚜虫与寄主植物之间的对应关系.