梨的英语作文

篇一：英语作文

My favourite season

Class Four Grade FiveTian Peiyan

I like four seasons !

Look at the green trees and pink flowers . It`s spring. I like it. Because I can go on a picnic and there are beautiful flowers everywhere.

The weather is very hot. hot. hot ! It`s summer. I like it. Because I can go swimming and eat ice cream.

What lovely colours! The leaves fall and fall and fall. It`s fall . I like it. Because I can pick pears and I want to draw pictures , too. There is lots of snow. It`s white everywhere. It`s winter. Because I can play in the snow, make a snowman and I like winter vacation. 翻译：我最喜爱的季节

看绿色的树和粉色的花。那是春天，我喜欢它。因为我可以去野餐而且到处都有美丽的花。

天气非常的热，热，热！那是夏天，我喜欢它。因为我可以去游泳而且还可以吃冰激凌。

多么美丽的颜色！叶子落啊落啊落。那是秋天，我喜欢它。因为我可以摘梨而且我还想画一幅画。

有很多雪，到处都是白色的。那是冬天，我喜欢它。因为我可以玩儿雪，堆雪人，我很喜欢寒假。

（指导教师：张艳阳）

篇二：蒲螨对梨小食心虫的控制作用(英文)

Control Study of Parasitic pyemotes sp. against Oriental Fruit Moth (Grapholitha molesta Bussck)

ZHOU Wei1, ZHONG Han-dong2, HUANG He-ping2, DONG Li-kun2*, OU Ke-fang2, LI Chuan-ren1

1. Collage of agriculture, Yangtze University, Hubei Province, Jinzhou 434100, China; 2. Wuhan Landscape Gardening Institute, Hubei Province, Wuhan 430081, China

Abstract [Objective] The paper was to study the parasitic ability and field control effect of pyemotes sp. against oriental fruit moth (Grapholitha molesta Bussck) which caused damage on Photinia. [Method] The indoor infection test and field control test of pyemotes sp. against oriental fruit moth was carried out. The parasitic ability and activity characteristic of pyemotes sp. were observed, and the effect of environmental factors such as humidity and temperature on the parasitic ability of pyemotes sp. was studied. [Result] Pyemotes sp. had good control effect on oriental fruit moth under the proper conditions; the host searching abilities of pyemotes sp. were different at different temperature and humidity conditions, humidity had large impact on the activity of pyemotes sp., while temperature had large impact on the individual activity. [Conclusion] The result showed that pyemotes sp. had effective control effort on oriental fruit moth.

Key words Pyemotes sp.; Biological control; Oriental fruit moth

Oriental fruit moth (Grapholitha molesta Bussck) is a worldwide pest of fruit trees. It mainly causes damage on the fruits and young shoots of fruit trees in Rosaceae such as pear, peach, plum, apricot, apple and hawthorn, which also is the main pest of plants in Rosaceae such as flowering peach, Photinia serrulata Lindl. and Prunus cerasifera Ehrh. The pest damages the young shoots in the form of larva, causing a large number of shoots wither on the top. This seriously affects the growth and the ornamental value of ornamental trees and shrubs. It has serious occurrence in the valley of Yellow River and Yangtze River in China during May to September, which has the characteristics of hidden damage, more occurrence and serious overlapping of generations, long damage time and complex hosts, leading to many difficulties in the chemical control and sex pheromone trapping[1-2]. Pyemotes sp. is a class of new natural enemy source, which has obvious control effect on the hidden pests such as bark beetle and stem borer, and also has the characteristics of rapid reproducti(来自:www.Zw2.cn 爱 作文 网)on speed and being convenient for mass production[3-4]. Taking artificially cultured Pyemotes sp. as the bio-control material, the author preliminarily explored the parasitic capacity and field control effect of the parasitic mite against the oriental fruit moth. 1 Materials and Methods

1.1 Test pest and plant

Pyemotes sp. was provided by Wuhan Landscape Gardening Institute, and oriental fruit moth was collected from the branches of P.serrulata in Wuhan Landscape Gardening Institute.

1.2 Experimental methods

1.2.1 Determination of the infection ability of Pyemotes sp. against oriental fruit moth

4th instar of larvae of oriental fruit moth was taken as the test pest. A head of oriental fruit moth larva was placed in the Petri dish with the diameter of 9 cm. according to the different inoculation amount of mite, 1, 2, 3, 4, 5, 6 and 7 heads of Pyemotes sp. were separately inoculated in each dish with five repeats in each treatment. After inoculation, the living state and death condition of oriental fruit moth were observed once every 6 h, so as to evaluate the parasitic and lethal capability of Pyemotes sp. against oriental fruit moth.

1.2.2 Observation of the diffusion behavior of Pyemotes sp.

According to reports, Pyemotes sp. had the habits of crawling upward. In order to substantiate or disprove its habit, the following tests were specially designed. Six long tubes with the length of 10 cm were taken and marker at 5 cm in the middle, and the cotton plugs carrying a certain amount of Pyemotes sp. were used to block orifices.

When Pyemotes sp. was inoculated, No. 1-3 tubes were stood upside down in test tube rack (denoted as treatment A, Pyemotes sp. was in the lower part), and No. 4-6 tubes were stood upright in the rack (denoted as treatment B, Pyemotes sp. was at the top). The distribution of Pyemotes sp. in the tube was observed under microscope after 24 h.

1.2.3 Effect of humidity on the individual activation ability of Pyemotes sp.

Pyemotes sp. is mainly used to control borer pests, which needs to enter the borer channel during the searching process for host. However, there are much bleed liquid secreted by main plant and the wastes of pest in the channel of borer pests, causing a larger humidity in borer channel. Pyemotes sp. is relatively small, which is easy to be affected by the water factors in the borer channel with large humidity. Therefore, the effect of indoor surface humidity on the activation ability of Pyemotes sp. was carried out. According to the method on studying the crawling speed of Pyemotes sp. by ZHANG Zuo-shuang[4], the crawling speed of the mite under moisturizing condition was determined. 0, 0.5, 1.0, 1.5 and 2.0 ml distilled water was evenly added into the Petri dishes which had been covered with filter paper (diameter 12.5cm) on the bottom by pipette gun, and they were settled as five treatments. When Pyemotes sp. was inoculated on filter paper, the crawling line was tracked under microscope, and the crawling track was drawn. The length of crawling track within 60 s was measured, and its crawling speed was calculated. Each treatment contained ten repeats, and the average value of crawling speed under each humidity treatment was finally calculated.

1.2.4 Effect of temperature on the individual activation ability of Pyemotes sp.

There are much weathers with extremely high temperatures in Wuhan City, and Pyemotes sp. released in field is bound to be affected by high temperature. Therefore, the author studied the effect of temperature on the activity of Pyemotes sp., in order to find the best survival temperature range of the mite. Pyemotes sp. was placed in different temperatures for a certain time, and the effect of temperature on the activity of Pyemotes sp. was observed. Ten heads of Pyemotes sp. were inoculated in each temperature, and the temperature treatments were set as follows: 0, 5, 10, 15, 20, 25, 30 and 35 ℃. Each temperature contained three repeats. The survival condition of Pyemotes sp. was checked under microscope once every 1 d after inoculation. The number of deaths per day was recorded, and the test would be ended after 8 d.

1.2.5 Determination of field control effect of Pyemotes sp. against oriental fruit moth

Twenty-five P. serrulata located in Wuhan Landscape Gardening Institute which had been damaged by oriental fruit moth were selected to carry out field control test. The damage degree of oriental fruit moth was investigated before the release of Pyemotes sp., and found that there were about 5-9 branches in the tree which had been damaged by oriental fruit moth. The feeding tubes for Pyemotes sp. were placed in envelopes, and these envelopes were placed in the lower part of the trunk for hanging release. Different release amount of Pyemotes sp. was set as treatment, and 1, 2, 3, 4 and 5 tubes of Pyemotes sp. (each tube contained approximately 20,000-30,000 heads of Pyemotes sp.) were released in each tree. Five P. serrulata were treated in each release amount as five repeats. In addition, five P. serrulata without inoculation of Pyemotes sp. were set as control. The P. serrulata in each treatment and control were randomly arranged in the nursery, and the crown of each tree for the test was separated with the other’s, avoiding the mutual interference between the treatments.

After release for 10 d, the parasitic condition of Pyemotes sp. on oriental fruit moth was investigated.

2 Results and Analysis

2.1 Infection ability of Pyemotes sp. against oriental fruit moth

The experiment showed that oriental fruit moth would have two states after the biting of Pyemotes sp. They would first have paralysis status, and then the pests could not crawl with body overturning and convulsions from time to time. As the number of biting times by Pyemotes sp. increasing, the larvae of oriental fruit moth would enter the death state. In addition, according to the biting infection of Pyemotes sp., oriental fruit moth also had a self-defense behavior. It would weave a silk-like structure through spinning to surround itself, then it would crawl and flip back and forth within the structure and try to get rid of the attack of Pyemotes sp. As shown in Table 1, when a head of Pyemotes sp. was inoculated in each dish for 24 h, there had individuals of oriental fruit moth been bite by Pyemotes sp. among five repeats, but oriental fruit moth still maintained an active state; when two heads of Pyemotes sp. were inoculated in each dish for 24 h, oriental fruit moth had self-defense behavior; when three heads of Pyemotes sp. were inoculated in each dish for 12 h, oriental fruit moth spilt filum for self-defense, and the pests in two repeats were palsied; after 18 h, all the pests in the treatment were in paralysis state and lost their crawling ability, indicating that oriental fruit moth had been controlled by Pyemotes sp.; all the pests in the treatment died after 24 h; when four heads of Pyemotes sp. were inoculated in each dish, oriental fruit moth in four repeats were palsied after 6 h, and all the pests in five treatments died after 12 h; when five heads of Pyemotes sp. were inoculated in each dish, four heads of oriental fruit moth in five repeats died, and one head was palsied; they were all died after 12 h; oriental fruit moth in the treatments inoculated with six and seven heads of Pyemotes sp. all died within 6 h after inoculation.

2.2 Crawling and diffusion habits of Pyemotes sp.

As shown in Table 2, when the tube was inverted (Pyemotes sp. was in the lower part of test tube), 315 heads of Pyemotes sp. climbed to the part over 5 cm after 24 h, and only 33.00% of the mites remained in the lower part, indicating that Pyemotes sp. had significant habit of crawling up. When the tubes were stood upright (Pyemotes sp. was in the uuper part of test tube), 472 heads of Pyemotes sp. still remained in the part over 5 cm after 24 h, but 30.70% of Pyemotes sp. climbed

down to the lower tube, indicating that Pyemotes sp. had downward diffusion habit. The test showed that Pyemotes sp. both had upward and downward diffusion habit, and the upward diffusion habit was much stronger. Therefore, when Pyemotes sp. was tended to release in field, the habits of crawling and searching upward should be considered, and the release site should be in the middle and lower parts of plants.

2.3 Effect of humidity on the host searching ability of Pyemotes sp.

The test showed that humidity had significant effect on the host searching ability of Pyemotes sp., the greater the humidity was, the weaker the host searching ability was (Table 3). The average crawling speed of Pyemotes sp. in the filter paper without water reached 0.26mm / s; when 0.5 ml water was added to filter paper, the average crawling speed of the mite slightly decreased as about 0.19mm / s; when 1.0 ml water was added to paper, the average crawling speed of the mite significantly decreased as only 0.08mm / s; when 1.5 ml water was added to paper, Pyemotes sp. could only crawled for 1 mm within 60 s, some mites even could not crawl; when 2 ml water was added to paper, water film was formed in the surface of filter paper, and Pyemotes sp. was bounded by water film without crawling.

2.4 Effect of temperature on the survival time of Pyemotes sp.

As shown in Table 4, when there was no offering of host, Pyemotes sp. would had large number of death individuals in short time at low temperature below 5 ℃ and high temperature above 30 ℃, and they could survive for longer time in the temperature range of 10-30 ℃ with low mortality of individuals, and the most individuals in all treatments would die at about 8 d. When the temperature was 0 ℃, 11 heads of Pyemotes sp. died within 24 h, and all the mites died at 4 d. With the increasing of processing temperature, the individual survival time and survival amount of Pyemotes sp. also increased. However, when the temperature was above 30 ℃, the individual mortality of Pyemotes sp. increased again. The lasting time without appearance of death individual was the longest under the temperature of 15, 20 and 25 ℃; followed by 30 ℃, which began to have death individual at 5 d. Therefore, the optimum temperature for the survival of Pyemotes sp. should be 15-30 ℃, and the field release should be carried out in this temperature range in order to avoid the adverse impact of environmental temperature factors on Pyemotes sp.

2.5 Control effect of Pyemotes sp. against oriental fruit moth

Different amount of Pyemotes sp. were released in the nursery in Wuhan Landscape Gardening Institute, and the survival and the parasitic condition by Pyemotes sp. of oriental fruit moth in various damaged parts in top shoot of P. serrulata were investigated after 10 d. The larvae of oriental fruit moth were found to be parasitized, survival Pyemotes sp. was also found in the borer channel of oriental fruit moth, and Pyemotes sp. with swelling abdomen were found in the dead body of oriental fruit moth( Fig. 1). As shown in Fig. 5, with the increasing release amount of Pyemotes sp., the parasitized rate of oriental fruit moth also increased. When five tubes of Pyemotes sp. were released, the parasitized rate of oriental fruit moth was up to 79.31%, and the lowest parasitized rate of the pest was above 25.00%. Therefore, the test showed that Pyemotes sp. had strong control effect on the population of oriental fruit moth in field.

3 Conclusion

Crawling and diffusion test showed that Pyemotes sp. had the habit of crawling upward, so the characteristic could be utilized in field release. The release device for Pyemotes sp. could be placed in the lower part of plant so that the released Pyemotes sp. could find the host upward along the trunk. In addition, the study on the effects of environmental factors such as humidity and temperature on the individual activation ability and activity showed that humidity had large impact on the activation ability of the mite. This was a limiting factor for the natural enemy of borer pests. The borer channel of most borer pests such as stem borer, bark beetle and leafrollermoth had much moisture or mucilage secreted by plant tissue, so the humidity was also large, this was easy to affect the crawling of Pyemotes sp. for searching host. Furthermore, high temperature in summer in Wuhan region also had great impact on the individual activity of Pyemotes sp., when the temperature reached 35 ℃, the individual survival ability of Pyemotes sp. was affected. Therefore, the application of the natural enemy should consider the impact of humidity and temperature on the enemy.

Through the determination of infection ability of Pyemotes sp. against oriental fruit moth, it was found that three heads of Pyemotes sp. could make a head of 4th instar larva of oriental fruit moth sustain in paralysis state, thus making the pest losing its ability of continuous damage. In addition, more than five heads of Pyemotes sp. could make a head of 4th instar larva die, so Pyemotes sp. had strong parasitic ability on oriental fruit moth. Through field determination test, it was found that release of Pyemotes sp. in field also had good control effect on oriental fruit moth. Oriental fruit moth has become the stem borer with common occurrence in fruit trees and ornamental plants, and Pyemotes sp. is the new enemy source for the control of stem borer. Yield test also confirmed that the control of Pyemotes sp. against oriental fruit moth is effective.

Table 1. The infection ability of pyemotes sp. on the larvae of oriental fruit moth

2 3

4

5

6

7 5 5 5 5 5 5 0 0 4 1 0 0 0 0 0 4 5 5 0 2 0 0 0 0 0 0 5 5 5 5 0 5 0 0 0 0 0 0 5 5 5 5 0 0 0 0 0 0 0 5 5 5 5 5

Table2. The distribution condition of pyemotes sp. in tube Distribution part Treatment B Treatment A

Lower than 5 cm 154 209

Higher than 5 cm 315 472

Table3. Crawling speed of pyemotes sp. on the filter paper with different humidity //ml n time //s distance //mm/s //mm

0 60 11.5~21.0 0.26

0.5 60 9~15 0.19

1.0 60 3~8 0.08

1.5 60 0~1 0.01

篇三：作文：梨乡美景

梨乡美景

阿坝州金川县东方红小学校五年级一班：李治枰

我的家乡日照充沛，气候温和，鸟语花香，有阿坝“小江南”之美称。 从阿坝州州府马尔康驱车南行两个多小时后，就会到素有“雪梨之乡”

美誉的阿坝新江南──金川。这里有雪域高

原规模最大的梨花和红叶奇景，是全国闻名

的雪梨产区。无论河坝沃土还是半山坡地，

漫山遍野都栽种着梨树。阳春三月，万亩梨

海，百里白蕊，家乡整个河谷似茫茫雪海。

在暖暖的阳光照耀下，梨花迎着微风，张开了笑脸。当你站在梨园的最高处，放眼望去，漫山遍野，白茫茫的一片，像起伏的白色的浪花。这时，一定会让你真正感受到“千树万树梨花开”奇景。瞧!那圣洁的白色，白得朦胧，白得素洁淡雅，多么像漫天的大雪落满枝头呀！当你走进梨树林中，你再瞧！这人见人爱的叶儿在白得如雪的梨花

中，探出了一点儿小脑袋，好像一位小姑娘十

分害羞。那娇小可爱的梨花挂满枝头，好像一

串串银铃，花儿们你拥我挤，好像赶集似的。

微风吹过，又好似小铃铛挂满枝头，正在叮当

作响，让人看了十分惬意。五个花瓣间簇拥着淡黄色的花蕊，像一丝月光洒向了花朵的中心，真是美极了！当清晨第一缕阳光洒向梨树，花儿就变得更加透明，嫩嫩的，像娃娃白嫩的小脸蛋儿，让人看了心旷神怡！

听爷爷讲，金川梨树栽培历史悠久，梨果历代都是进京贡品，有“金皇果”、

“公主梨”的美誉。还有著名的鸡腿梨、金花梨、水冬瓜梨、红花

梨、麻籽梨、蜂蜜梨等。其中鸡腿梨、金花梨品质

超群，独树一帜，果肉细嫩，酸甜多汁，被国内外

果树专家视为世界梨果品种中的佼佼者。 当梨儿

成熟时，已是金秋十月，这时的家乡硕果飘香，梨

果挂满千树万株枝头，浓浓梨香飘出十里之外。十

月之后，顺河而下，沿河两岸热气腾腾，整个金川的大地宛如熊熊燃烧的“火焰”，到处都是浓艳的色彩，到处都是缤纷的落叶，仿佛让你在不经意间闯入了童话世界，那偶尔从树上飘下来的红叶，犹如一只只金黄的蝴蝶在梨树林间翩翩起舞。抬头，眼里是红叶，低头，脚下还是红叶，漫步林间，脉络分明的红叶从空中斜斜地飞过来，信手接在掌心，轻轻收藏，便成了小朋友们天然的书签、粘帖材枓??。

看见了吧!我的家乡是这么美丽，这么神奇。

如今，随着家乡旅游业的深入发展，我相信，在

不久的将来，我的家乡一定会变得更加美好，家

乡的人民一定会过上更加幸福的新生活。

指导教师：张登礼