Impact of harvesting time and fruit firmness on the tolerance to fungal storage diseases in an apple germplasm collection

Blue mold and bitter rot, caused by Penicillium expansum and Colletotrichum gloeosporioides, respectively, are two of the most devastating diseases during and after storage of apple. The present project was conducted to evaluate the level of tolerance to these diseases in apple germplasm, and investigate possible associations with other fruit characteristics such as harvest date, firmness at harvest, softening (loss of firmness during storage) and sun-exposure. Apples were harvested at a maturation stage suitable for storage, inoculated with spore suspensions of P. expansum (127 cultivars) or C. gloeosporioides (70 cultivars), and stored for 6 or 12 weeks for early- and late-maturing cultivars, respectively. Fruit firmness was measured after harvest and after storage, and the difference was used as a measure of fruit softening. Average lesion diameter varied significantly among both early- and late-maturing cultivars. The amount of damage caused by the two diseases was significantly correlated across cultivars. Regression analyses indicated that lesion diameter was positively affected by fruit softening and negatively affected by harvest date and firmness at harvest. Impact of the independent variables was quantified with partial least squares discriminant analysis; approximately 40% of the genetic variation could be explained by these variables with harvest date being the most important. The effect of sun-exposure was analyzed on six bi-colored cultivars but the results were not conclusive. Cultivars that showed relatively small symptoms in spite of being early-maturing and/or only medium firm, may have other traits that are beneficial for storage and could therefore be especially useful in breeding programs.     

Control of Penicillium expansum with potassium phosphite and heat treatment

Potassium phosphite (Phi) was evaluated for its in vitro activity against Penicillium expansum and for its potential long-term efficacy against postharvest blue mold infections on apple fruit. Phi amended to malt extract agar medium at 2 and 4 mg/ml completely inhibited mycelial growth and conidial germination, respectively. Conidia of P. expansum suspended for 3 min in a solution of 2 mg/ml Phi at 20 °C or heated to 50 °C germinated at 53 and 0%, respectively. Disease incidence of P. expansum on Elstar apples wounded and inoculated with a thiabendazole-resistant isolate was reduced significantly (P = 0.01) following a curative treatment with Phi at 2 mg/ml. When applied on freshly harvested unwounded Elstar apples, Phi (2 mg/ml) reduced blue mold incidence about three-fold compared to the control and was found to be as effective as thiabendazole against natural blue mold infections after six months of storage at 2 °C. Our results suggest that potassium phosphite has a potential to be part of the general management program implemented for the control of postharvest blue mold infections on pome fruits.     

出口竹制品防霉现状及其研究进展

通过调查了当前企业的防霉现状，并查阅相关文献，针对存在的问题分析探讨，拟从霉变真菌种类调查及霉变特性、防霉剂的筛选及处理方法、综合防霉措施3个方面开展研究工作。     

板坯连铸结晶器内凝固坯壳的三维数值模拟

基于流场和温度场的计算,对断面为1 780 mm×225 mm的板坯结晶器进行数值模拟,考虑3种不同水口条件下,钢液流动对凝固壳的冲刷,计算出凝固壳厚度的三维分布特征,并与二维切片法的计算结果进行了对比。结果表明：有水口时结晶器角部位置凝固壳最大值为约45 mm,宽面和窄面中心凝固厚度壳最大值为24 mm,分别比无水口条件下凝固壳薄1~2 mm;钢液的扩散会使凝固壳在距离结晶器角部300 mm和顶部400 mm的位置形成约深度2.5 mm的凹陷;同时钢液会冲刷整个结晶器窄面的凝固壳,在窄面中心最严重;对比不同的水口,凸底水口冲刷最大,凹底最小。     

20%寡聚酸碘水剂对黄瓜灰霉病的药效试验

20%寡聚酸碘水剂（AS）的有效成分为氨基寡糖素与碘的络合物,采用室内生物活性测定及田间药效试验,以50%乙烯菌核利可湿性粉剂（WP）1 000倍液为对照药剂,评价了20%寡聚酸碘AS对黄瓜灰霉病的防治效果。室内抑菌试验结果表明：20%寡聚酸碘AS 1 000倍液、1 500倍液、2 000倍液的抑菌率分别为97.30%、45.90%、14.00%,均低于50%乙烯菌核利WP 1 000倍液（100.00%）。田间药效试验结果表明：20%寡聚酸碘AS 1 000倍液、1 500倍液的田间防效分别为81.66%、74.80%,均高于50%乙烯菌核利WP 1 000倍液（73.87%）。     

霉菌在抗生素发酵过程中的危害及防治

霉菌属于微生物中的一类真菌,它在代谢过程中产生的许多毒素具有抗菌、抗原虫和抗真菌的能力,对抗生素发酵具有非常大的危害和破坏力。本文综述了霉菌在抗生素发酵中的危害和特性,以及在抗生素发酵中对于霉菌如何进行有效的防治处理。     

6种杀菌剂对设施番茄灰霉病的防治效果

采用温室试验方法,研究咯菌腈、啶酰菌胺、嘧霉胺、乙霉威.多菌灵、腐霉利和甲基硫菌灵6种杀菌剂对设施番茄灰霉病的防效,以筛选防治番茄灰霉病的理想药剂。结果表明,6种杀菌剂对番茄灰霉病均有一定的防治效果。其中50%啶酰菌胺(用量750g/hm2)、50%咯菌腈(用量750g/hm2)2个处理对番茄灰霉病防治效果显著,对病叶和病果的平均防效分别达79.16%、87.95%和77.20%、85.84%;40%嘧霉胺(用量1 550g/hm2)、60%乙霉威.多菌灵(用量1 800g/hm2)2个处理对番茄灰霉病也有一定的防治效果,对病叶和病果的平均防效分别为63.15%、66.71%和70.48%、62.65%;50%腐霉利(用量1 500g/hm2)、70%甲基硫菌灵(用量2 580g/hm2)对番茄灰霉病的防效相对较差。     

Outdoor Mold-resistance and Flame Retardance of Pinus massoniana Treated with Nano-ZnO

The effect of nano-ZnO,at concentrations of 2.0,10.0,20.0,and 40.0 g·kg^-1,on mold resistance and flame retardance of Pinus massoniana was studied.Results showed that both drug loading and mold resistance improved as the concentration of nano-ZnO increased with the time to mold initiation for the treated P.massoniana being 3-4 weeks longer than the untreated.The time to ignition（TTI） of P.massoniana treated by nano-ZnO at 2.0 g·kg^-1 was 7 s later than the untreated sample,and the total smoke release（TSR） with 20.0 g·kg^-1 was lower than the untreated.The treated P.massoniana differed slightly from the untreated in heat release rate（HRR）,total heat release（THR）,mass loss rate （MLR）,and effective heat of combustion（EHC）.     

98-8番茄的选育

98-8番茄为中早熟品种,无限生长型,第8～9片叶着生第一穗花,果实编高圆形,无青肩,平均单果重250～300g,果色粉红,果肉较厚,硬度高,耐裂果,耐贮运.一般667 m2产量5 000kg以上.田间表现高抗叶霉病(cf5基因).     

Effect of treating soybean with 2,6-dichloroisonicotinic acid (INA) and benzothiadiazole (BTH) on seed yields and the level of disease caused by Sclerotinia sclerotiorum in field and greenhouse studies

Field or greenhouse grown soybeans were treated with 2,6-dichloroisonicotinic acid or benzothiadiazole and subsequently assessed for severity of white mold disease caused by Sclerotinia sclerotiorum. Three or four applications of 2,6-dichloroisonicotinic acid to field plots in 1993–1995 reduced severity of white mold after natural infection by 20–70% compared with water-treated controls in soybean cultivars Elgin 87 and Williams 82, which are considered to be highly susceptible to the disease. The effect was not as large in the cultivars Corsoy 79 and NKS19-90 which are more resistant to white mold. Two or four applications of benzothiadiazole to field plots in 1995 and 1996 reduced white mold severity by 20–60%, with the greatest reductions again observed in the more susceptible cultivars. Corresponding yields were increased compared with controls, particularly for the susceptible cultivars under conditions of high disease pressure. In greenhouse trials multiple applications of either compound resulted in significantly smaller lesion diameters following subsequent leaf inoculations with the fungus. The compounds did not result in observable phytotoxicity or inhibit growth of Sclerotinia sp. in vitro. We hypothesize that the decrease in disease severity following treatment with INA or BTH is a result of resistance induction.