What Is RKN (Root Knot Nematode)?
If you grow figs in a hot climate, with mild and short winters, you should become familiar with RKN.
Root-knot nematodes are very small parasites that exist in the soil and feed on plant roots. RKN symptoms on fig tree roots can be dramatic, especially in hotter climates, with mild and short winters. Florida is especially susceptible to RKN. As a result of nematode feeding, large galls or “knots” can form throughout the root system of infected trees. Severe infections can result in reduced fig production and quality. Some fig varieties resist root-knot nematode infestation well.
While most evidence of root-knot nematode damage occurs below ground, numerous symptoms can also be observed above ground. Severely affected fig trees will often wilt easily. Because galled roots have only a limited ability to absorb and transport water and nutrients to the rest of the tree, severely infected trees may wilt even in the presence of sufficient soil moisture, especially during the heat of afternoon sun. Fig trees may also show signs of nutrient deficiency symptoms because of their reduced ability to absorb and transport nutrients from the soil. Additional fertilization may not even help combat the effects of root-knot nematode-induced chlorosis. Stunting is often observed in fig trees grown in root-knot nematode-infested fields, and fig production is reduced.
