绿化苗木不宜混栽
Green seedlings should not be mixed
一般来说，营造两种以上的混栽林，可改善土壤条件，提高防护效果，但是混栽不当，不但树种间相互抑制生长，而且病虫害发生严重，给生产造成不应有的损失。下面就举出几种不宜混栽的组合:
Generally speaking, the construction of more than two kinds of mixed plantation can improve the soil conditions and improve the protection effect, but the improper mixed planting not only inhibits the growth of trees, but also causes serious diseases and insect pests, which will cause the production of undue losses. Here are a few combinations that should not be mixed:
一、苦楝与桑树混栽苦楝树体内普遍存在一种叫楝素的有毒物质，它对昆虫有较大拒食内吸、抑制发育和杀灭作用，对蚕同样有毒性，它的花毒性更大，如果落于桑园内，有毒物质挥发熏蒸后，采叶饲蚕即会发生急性中毒。
1. There is a kind of toxic substance called neem in Melia azedarach mixed with mulberry. It has a great effect of resisting food and inhaling, inhibiting development and killing insects. It is also toxic to silkworms, and its flower toxicity is greater. If it falls in mulberry garden, it will cause acute poisoning after volatilization and fumigation.
二、橘树与桑树混栽橘叶的汁液是多种成分组成的混合物，其中主要有芳香油、单宁及多种有机酸等物质，对蚕能起过敏反应的物质主要是芳香油类。芳香油能引起蚕忌避拒食和产生胃毒作用，对养蚕极为不利。
2. The juice of orange leaves mixed with mulberry is a mixture of various components, including aromatic oil, tannin and a variety of organic acids, and the substances that can cause allergic reaction to silkworm are mainly aromatic oil. Aromatic oil can prevent silkworms from eating and produce stomach toxicity, which is very harmful to sericulture.
三、桧柏与苹果、梨树、海棠混栽桧柏与苹果、梨树、海棠混栽或在果园附近栽植桧柏，就容易发生苹桧锈病。苹桧锈病主要为害苹果、梨、海棠的叶片、新梢和果实，而桧柏就是病菌的转主寄主。这种病菌在为害苹果、梨树、海棠后，转移到桧柏树上越冬，为害桧柏的嫩枝，次年继续为害苹果、梨、海棠，因此，它们不能混种在一起。
Third, juniper and apple, pear, Begonia mixed planting juniper and apple, pear, Begonia mixed planting or planting juniper near the orchard, it is easy to have apple juniper rust. Apple juniper rust mainly damages the leaves, shoots and fruits of apple, pear and begonia, and juniper is the host of the pathogen. After damaging apple, pear and begonia, the pathogen transferred to juniper tree for overwintering, damaging juniper's twigs, and damaging apple, pear and Begonia the next year. Therefore, they cannot be mixed.
四、云杉与李混栽混栽后容易发生云杉球果锈病，感病球果提早枯裂，使种子产量和质量降低，严重影响云杉的天然更新和采种工作。
4. After the mixture of spruce and plum, spruce cones are prone to rust, and susceptible cones wither early, which reduces the seed yield and quality, and seriously affects the natural regeneration and seed collection of spruce.
五、柑橘、葡萄与榆树混栽榆树是柑橘星天牛、褐天牛喜食的树木。若在柑橘、葡萄园栽植榆树，则会诱来天牛大量取食和繁衍，转而严重为害柑橘。此外，还易造成葡萄减产。
5. The mixed planting of orange, grape and elm is the favorite tree of Citrus star longicorn and brown longicorn. If elms are planted in citrus and vineyards, it will induce the longicorn to feed and reproduce in large quantities, which will damage the citrus seriously. In addition, it is easy to reduce grape yield.
另外，果园附近也不宜栽植泡桐。果树的根部常发生紫纹羽病，轻者树势衰弱，叶黄早落，重者枝叶枯干，甚至会全株死亡。泡桐是紫纹羽病的重要寄主，因而加重果园紫纹羽病的发生。
In addition, Paulownia should not be planted near the orchard. The roots of fruit trees often suffer from purple feather disease, the light ones are weak, the leaves are yellow and fall early, the heavy ones are withered, and even the whole plant will die. Paulownia is an important host of purple feather disease, which aggravates the occurrence of purple feather disease in orchard.