Humans have co-existed with leeches for so long, according to Siddall, that just about every language has a word for leech. 3. theyâve made a comeback in medicine.
The lettuce aphid is a problem worldwide and has recently become problematic in the western United States and Canada (Liu and McCreight 2006; McCreight 2008). However, the first three species of aphids listed above are most economically damaging in Florida (Nuessly and Webb 2010). Although heavy aphid pressure can stunt plants, the major problem aphids cause is head contamination, which makes lettuce unmarketable.
Aphid Damage In the Vegetable Garden. A few aphids on your vegetable plants is not much to worry about; they wonât do a bunch of damage. Large populations of aphids can severely damage plants cauing leaf curl, wilting, yellowing leaves, and stunted growth. Many times a sure sign of aphids on your plants is the presence of ants. Ants are attreacted to a sweet substance secreted by aphids called honeydew.