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The injurious insects of cotton of this province, however, have not hithertobeen carefully studied, especially the pink bollworm, which annually reducesthe cotton production by 10 to 30 per cent. The present authors spent twoyears in observing the life history and habits of this insect, in attempting tofind some effective control measures. The result is herewith summarized :- 1. In the vicinity of Wu-chang, the pink bollworm has three generationsa year. The first generation occupies May and July. The second... The injurious insects of cotton of this province, however, have not hithertobeen carefully studied, especially the pink bollworm, which annually reducesthe cotton production by 10 to 30 per cent. The present authors spent twoyears in observing the life history and habits of this insect, in attempting tofind some effective control measures. The result is herewith summarized :- 1. In the vicinity of Wu-chang, the pink bollworm has three generationsa year. The first generation occupies May and July. The second one occursin mid-July and the last in late-August. Due to the lower temperature, theemergence of the first generation need about two months. 2. In day time, the adult is usually inactive, while in windless night,after seven o'clock, it becomes very active and lays eggs mostly on green bollsand calyx. about a week later, the eggs hatch and the newly-hatched larvaeare shortly getting into the bolls. After four days they often eat into theseeds. Ten days later, the lint is so stunted as to become dusky yellow incolor, thus both the yield and the quality of cotton are greatly lowered. Themature larvae appear about half a month after. 3. Field experiments have shown that three dustings of 10% DDT- sulfurpowder were very effective. In the severely damaged cotton area, the thirdspray may be simultaneously done with controlling the cotton leaf-hoppers andthe cotton leaf-rollers. 4. About 84% hibernating larvae in cotton seeds will come out when thecotton exposed in sun light and stored in the farmer's house. Hence it seemsadvisable to put cloth or other soft material covers on the cotton stored inorder to collect and kill the larvae under them. In addition, destruction of allremaining bolls on the cotton stalks, as early as possible in winter is important. 5. For controlling the bollworms in cotton store-houses, the followingresults have been obtained 50% wettable DDT diluted with 20 parts of water,91% of larvae were killed within 30 days; 6.5% 666 (benzene hexachloride)gave a mortality of 63% in four months. Wettable 6.5% 666 diluted withwater (1:100), has been proved to be the most effective ovicide which destroys99.4% of eggs while parathion (E605) also gave a very high mortality at97.7%. But 50% wettable DDT (1:100) Kills eggs at 64.2% and lead arsena-te only 16.2% respectively. 6. There were 39.1% overwintering larvae parasitized by parasitic mitesand wasps. Among them, most are the mite, Pediculoides ventricosus Newport,while the parasitic wasps Eurypterna arakawae Mats. less than 0.5%. 红铃虫在南方棉区为害棉花相当严重,除去脱落蕾铃外,僵黄花率为10—30%,我们针对这个严重问题,进行了红铃虫生活史的观察研究与防治方法试验,写出初步结果,提供防治参考。 1.红铃虫在华中武昌棉区一年有三代。第一代羽化在5至6月,7月中旬为第二代;8月下旬为第三代;第一代的蛹和幼虫所需时期均较第二、三代长。 2.成虫白天不活动,夜晚7时以后无风天气活跃最盛,产卵以在青铃上及花萼上为最多。孵化后三十多分钟即钻入棉桃内为害,4天即侵入棉籽内取食,10天棉瓤纤维呈僵黄状,半月后幼虫即可老熟(第三代的)。 3.田间防治红铃虫以10%滴滴涕硫磺粉喷三次效果显著,在后期棉虫严重地区可结合防治叶跳虫卷叶虫等同时进行。 4.籽花内的幼虫在群众家里及晒花时逃出84%,因此指导群众将籽花堆上加覆盖物,再结合帘架晒花是消减过冬红铃虫最经济有效的办法。 4.防治仓库越冬红铃虫以50%可混性滴滴涕1:30倍水溶液杀虫效果最佳。30天内死亡率达91%.6.5%可混性666(1:20)死亡率为63%。但是1:100倍的水溶液杀卵效率高到99.4%。稀释万分之一的E605为97.7%。50%可混性滴滴涕1:100杀卵率为64.2%,砒酸铃最差... 红铃虫在南方棉区为害棉花相当严重,除去脱落蕾铃外,僵黄花率为10—30%,我们针对这个严重问题,进行了红铃虫生活史的观察研究与防治方法试验,写出初步结果,提供防治参考。 1.红铃虫在华中武昌棉区一年有三代。第一代羽化在5至6月,7月中旬为第二代;8月下旬为第三代;第一代的蛹和幼虫所需时期均较第二、三代长。 2.成虫白天不活动,夜晚7时以后无风天气活跃最盛,产卵以在青铃上及花萼上为最多。孵化后三十多分钟即钻入棉桃内为害,4天即侵入棉籽内取食,10天棉瓤纤维呈僵黄状,半月后幼虫即可老熟(第三代的)。 3.田间防治红铃虫以10%滴滴涕硫磺粉喷三次效果显著,在后期棉虫严重地区可结合防治叶跳虫卷叶虫等同时进行。 4.籽花内的幼虫在群众家里及晒花时逃出84%,因此指导群众将籽花堆上加覆盖物,再结合帘架晒花是消减过冬红铃虫最经济有效的办法。 4.防治仓库越冬红铃虫以50%可混性滴滴涕1:30倍水溶液杀虫效果最佳。30天内死亡率达91%.6.5%可混性666(1:20)死亡率为63%。但是1:100倍的水溶液杀卵效率高到99.4%。稀释万分之一的E605为97.7%。50%可混性滴滴涕1:100杀卵率为64.2%,砒酸铃最差为16.2%。 6.越冬幼虫被寄生的平均有39.1%,发现天敌有二种,其中绝大多数是榖痒螨(Pediculoides ventricosus The purpose of this paper is to discuss Prof. method of analyzing two-way reinforced concrete slab. This method is based upon the equilibrium of forces under ultimate loading, and consequently the effect of plasticity of the material is included in consideration. If we use this method to design two way reinforced concrete slab, We should not only have much saving of steel, but also a saving of labour in computation. No matter that the slab is continuous over how many spans of unequal lengths, it can be easily... The purpose of this paper is to discuss Prof. method of analyzing two-way reinforced concrete slab. This method is based upon the equilibrium of forces under ultimate loading, and consequently the effect of plasticity of the material is included in consideration. If we use this method to design two way reinforced concrete slab, We should not only have much saving of steel, but also a saving of labour in computation. No matter that the slab is continuous over how many spans of unequal lengths, it can be easily analyzed, one by one, as a single span slab. 本文的目的是介紹蘇聯格娃斯捷夫教授的計算双向板的公式。這個公式是考慮板在極限平衡狀態,考慮了材料的塑性。用此方法計算雙向板,不但鋼筋經济而計算簡便。無論是多跨的板或不等跨的板,都可以视為單跨板來考虑,本文討論了格娃斯捷夫公式的基本理論,並将此理論应用到不規则形狀板的计算方面。 Experiments concerning the translocation of Systox of different concent-rations for the control of cotton aphids by means of water culture, seed treat-ment, soil application and spraying were conducted both in the greenhouseand field. Data are given which show that toxicants may be taken up byseeds, roots or leaves of cotton. A very good control of cotton aphids resultedin using soil application of 0.25% Systox water emulsion (about 2 catties ofBayer's concentrate per mou) for which the moderate toxicity is... Experiments concerning the translocation of Systox of different concent-rations for the control of cotton aphids by means of water culture, seed treat-ment, soil application and spraying were conducted both in the greenhouseand field. Data are given which show that toxicants may be taken up byseeds, roots or leaves of cotton. A very good control of cotton aphids resultedin using soil application of 0.25% Systox water emulsion (about 2 catties ofBayer's concentrate per mou) for which the moderate toxicity is retained atleast for 66 days in greenhouse and 23 days in the field. It is of great signi-ficance in agricultural practice to diminish labor and increase the residualeffect of control measures against the haphazard of aphids year after yearin the cotton belt of North China. E1059应用于棉花防治棉蚜的试验是分别在温室及田间进行的。无论浸种、水培、灌溉、喷射,它都有内导作用。此即说明棉花的种子、根或叶的组织都可吸收药液。随体液传输全体,使棉蚜产生内毒作用。从药效保持期来看,以药液灌溉最为持久。在温室内0.25%处理可保持66天;在田间(用1:400的稀释液。每亩800斤的用量)可以保持23天,如何使这个初步结果经济有效的应用於生产实践上,还需从多方面作最大的努力。
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