近幾年，江蘇省部分稻田水稻穎殼有褐色斑點，顏色發暗，外觀賣相不好。經分析，其成因主要有以下幾方麵，生產上應加以預防。

1、shuidaoshidanguoliangduiyingkesezeyingxiangzuida。jianshaodanfeiyongliang，shidangzengshilinjiafei，nengjianshaodaoguheke，tongshiyouliyutigaodaomipinzhihechanliang。zhuyaoshizaishuidaoyousuifenhuaqihuojianshufenlieqishiyonglinfei，kecushitangdeyunshu，jiasuguanjiangjieshi
，jieshilvheqianlizhongdounengdedaotigao；穗期施用鉀肥
，能增強植株後期的抗逆能力；而氮肥施用過多
，植株變得柔軟多汁，易倒伏和發生病蟲害，後期灌漿速度變慢，貪青遲熟，易導致水稻穎殼呈灰暗色。

2、daosuishangdaliangzilifahe，kenengyougukubingweihaizaocheng。gaibingshuzhenjunxingbinghai，bingjunyifenshengbaoziqizaidaogushangyuedong
，diernianshifangchufenshengbaozijiefengyuchuanbo，shuidaochousuihouqinhaihuaqiheyouying。huaqiyubaofengyu，daosuixianghumocazaochengshangkou，youliyubingjunqinru。shuidaochousuihou2-3周zhou危wei害hai幼you穎ying較jiao重zhong，初chu在zai穎ying殼ke頂ding端duan或huo側ce麵mian出chu現xian小xiao斑ban，漸jian發fa展zhan為wei邊bian緣yuan不bu清qing晰xi的de橢tuo圓yuan斑ban，後hou病bing斑ban融rong合he為wei不bu規gui則ze大da斑ban，擴kuo展zhan到dao穀gu粒li大da部bu或huo全quan部bu
，後hou變bian為wei枯ku白bai色se
，上shang麵mian有you許xu多duo小xiao黑hei點dian；水稻乳熟後受害，米粒變小，質地鬆脆，品質下降；水稻接近成熟時受害，僅在穀粒上有褐色小點，對產量影響不大。此外，水稻抽穗揚花期稻穀受腐生菌、稻瘟病、稻曲病浸染也易形成褐殼。

3、播bo栽zai期qi推tui遲chi，後hou期qi易yi受shou低di溫wen寒han露lu風feng影ying響xiang，如ru在zai灌guan漿jiang初chu期qi遇yu低di溫wen，灌guan漿jiang速su度du就jiu會hui變bian慢man，特te別bie是shi稻dao穗sui下xia半ban部bu的de稻dao粒li正zheng處chu於yu灌guan漿jiang敏min感gan期qi
，低di溫wen侵qin染ran後hou發fa育yu會hui停ting止zhi，結jie實shi率lv下xia降jiang

，隨sui後hou受shou腐fu生sheng菌jun侵qin染ran而er變bian褐he。

4

、灰hui飛fei虱shi在zai稻dao穗sui上shang取qu食shi，產chan生sheng大da量liang代dai謝xie物wu對dui色se澤ze影ying響xiang較jiao大da。近jin年nian來lai灰hui飛fei虱shi蟲chong量liang高gao於yu常chang年nian，水shui稻dao生sheng長chang後hou期qi灰hui飛fei虱shi若ruo蟲chong爬pa到dao稻dao穗sui上shang取qu食shi，數shu量liang大da時shi其qi分fen泌mi物wu可ke使shi稻dao穗sui變bian褐he。