瓜菜生長期由於病原菌的客觀存在

，一旦溫度和濕度適宜
，其發生發展到一定程度
，就會侵染秧苗甚至造成流行
，當秧苗茁壯或對水肥
、光照、溫度
、shidushidangtiaojieshi
，binghaidefashenghuijianqing。danshengchandexianshigaosuwomen，youyulianxuduochacidezhongzhishucai
，bingyuanjundeyuedongjizhuyuelaiyueduo，qizhongtuchuanbinghaidejilei，youjunbingcantidecunzai，haiyouzhengzaishengchangzhongdedaijunyuedongzhiwu，tebieshinuandongxianxiangdechansheng，shifenyouliyubingyuanjundehuodong，yijingdadaolebuyongyaowubaohu，guacaijiubunengzhengchangshengchangdechengdu。

從蔬菜播種的那一刻起，就生長在一個充滿病菌的“世界”裏(li)，如(ru)果(guo)不(bu)采(cai)取(qu)積(ji)極(ji)有(you)效(xiao)的(de)藥(yao)劑(ji)保(bao)護(hu)，而(er)單(dan)純(chun)依(yi)靠(kao)作(zuo)物(wu)自(zi)身(shen)的(de)抵(di)抗(kang)力(li)和(he)人(ren)為(wei)的(de)環(huan)境(jing)調(tiao)節(jie)使(shi)其(qi)正(zheng)常(chang)生(sheng)長(chang)，顯(xian)然(ran)是(shi)不(bu)現(xian)實(shi)的(de)。所(suo)以(yi)，蔬(shu)菜(cai)的(de)生(sheng)長(chang)發(fa)育(yu)期(qi)，也(ye)是(shi)人(ren)們(men)采(cai)取(qu)措(cuo)施(shi)與(yu)病(bing)菌(jun)的(de)抗(kang)爭(zheng)期(qi)，主(zhu)流(liu)觀(guan)點(dian)認(ren)為(wei)病(bing)害(hai)應(ying)“預防為主
，綜合防治”，非主流觀點認為“見病用藥，無病不防”。以下粗淺分析兩種觀點的利弊得失。

“見病用藥”的de基ji礎chu是shi建jian立li在zai發fa現xian中zhong心xin病bing株zhu之zhi後hou進jin行xing防fang治zhi
，生sheng產chan實shi踐jian中zhong，當dang田tian間jian發fa現xian中zhong心xin病bing株zhu時shi，往wang往wang已yi有you明ming顯xian的de症zheng狀zhuang，病bing菌jun孢bao子zi已yi不bu是shi初chu侵qin染ran階jie段duan，很hen可ke能neng是shi菌jun絲si生sheng長chang的de後hou期qi甚shen至zhi是shi產chan孢bao期qi，對dui植zhi株zhu生sheng長chang已yi造zao成cheng了le為wei害hai，特te別bie是shi生sheng產chan中zhong僅jin憑ping肉rou眼yan觀guan察cha，局ju限xian性xing和he誤wu差cha很hen大da，往wang往wang認ren為wei是shi中zhong心xin病bing株zhu，實shi際ji上shang已yi經jing形xing成cheng了le點dian片pian發fa生sheng
，以yi蔬shu菜cai霜shuang黴mei病bing為wei例li
，從cong點dian片pian發fa生sheng到dao大da麵mian積ji流liu行xing
，一yi般ban為wei2—3天
，因此，“見病用藥”duinongmindezhidaofeichangmohu，shiyongxingbuqiang，rongyizaochengyongyaowan，yanwufangzhizuijiashiqi，zaochenglianxuyongyaochengbengao，duanqineihenrongyizaochengjiaoyanzhongdehouguo。bizherenwei，shucaishengchangqijianzuodaowubingzaofangshixingzhiyouxiaodefangfa
，gaifangfazhidaosilumingque，nongminrongyizuodao
，shiyongxingjiaoqiang。zaishucaiweifabingzhiqian，yingyongbaohuxingdeshajunji，zaishucaidejingyebuweixingchengyicengyaojibaohuceng，yishikeyiyizhibingyuanbaozidemengfa，ershikeyizuzhijunsitideqinru，sanshikeyishasibufenyimengfahaimeiyoujinruyerouzuzhidejunsi。ruguofangzhidedang

，zuowuzhenggeshengchangqikeyibuyongzhiliaoxingdeshajunjijiunengshoudaolixiangdexiaoguo。tuiyibujiang，jishizuowuhouqidebing，bingqingmanyanyebuhuitaikuai，zaiyingyongzhiliaoxingshajunjihuixiaoguokuai
，rongyizhiyu。

以西紅柿晚疫病和黃瓜霜黴病的藥劑防治為例，當無病壯苗移栽之後，應立即噴施一次醚菌酯（阿米西達）或雙炔酰菌胺（瑞凡），總體預防效果優於百菌清或代森錳鋅類殺菌劑
，以後每隔7—10天再噴施1—2次ci，一yi般ban情qing況kuang下xia，西xi紅hong柿shi晚wan疫yi病bing和he黃huang瓜gua霜shuang黴mei病bing可ke以yi做zuo到dao不bu發fa生sheng或huo發fa生sheng很hen輕qing。當dang然ran，在zai秧yang苗miao移yi栽zai後hou已yi經jing發fa病bing，應ying立li即ji噴pen施shi治zhi療liao性xing的de殺sha菌jun劑ji，保bao護hu性xing的de殺sha菌jun劑ji此ci時shi用yong藥yao為wei時shi已yi晚wan，再zai噴pen施shi此ci類lei藥yao劑ji就jiu是shi勞lao民min傷shang財cai了le。