*8.3.1.2 Non-fumigant nematicides*

Non-fumigant nematicides are non-volatile dangerous substances that can be used before, during, and after planting to lower nematode population densities and protect crops from injury via drenching, drip irrigation, or spraying into crop foliage [41]. These nematicides are divided into two types: contact (which kills nematodes in the soil by direct touch) and systemic (which kills nematodes as they feed on plant roots). Non-fumigant chemicals are distributed by soil water movement after being applied to the soil. Non-fumigants' efficacy is not affected by soil temperature, unlike fumigant nematicides. Due to toxicity and environmental concerns, the many previous non-fumigant nematicides have been taken off the market. Prompting the creation of a new class of chemical molecules that address these issues while still providing effective plant-parasitic nematode management [41]. For usage in vegetable crops, some commercially non-fumigant nematicides are available (**Table 2**).


#### **Table 1.**

*Currently available chemical fumigant nematicides for use in the production of vegetables.*


#### **Table 2.**

*Currently available non-fumigant nematicides use in vegetable production.*

#### **8.4 Plants that inhibit the growth of nematodes**

Lesion and root-knot nematodes are suppressed by *Targets* species of marigolds. The most effective marigolds are Petite Blanc, Queen Sophia, Nemagold, and Tangerine (varieties include Petite Blanc, Queen Sophia, Nemagold, and Tangerine). Nematodes will nourish on and generate on *T. signata* or *T. tenuifolia*, *Signet* marigolds. Marigolds are ineffective against the northern root-knot nematode, *M. hapla*, which is found in colder climates. Marigolds provide the best impact when grown as a continuous planting for the full season [42].

The plant extracts effect from *Artemisia absinthium*, *Thymus vulgaris*, *Ricinus communis*, *Citrullus colocynthis*, and *Punica granatum* on the motility of *Meloidogyne incognita*, and *Helicotylenchus dihystera*, as well as the reversibility of the movement inhibition, were investigated by Korayem et al. [43]. *Megalaima incognita*'s egg-hatching inhibition and *H. dihystera*'s acetylcholinesterase (ACHEs) inhibition surprisingly, extracts of *P. granatum*, *A. absinthium*, and *T. vulgaris* and inhibited AChE more than oxamyl, which was previously thought to be a potent AChE inhibitor [44]. Similarly, detailed knowledge on the modes of action of various biological nematicides in terms of nematode acetylcholinesterase inhibition is required [10].

## **9. Conclusion**

Root-knot nematodes are potent silent killers of many plant species belonging to a wide range of plant families. They lower the yield of many economically important crops and decline the quality as well. Many farmers are unaware of their presence due to its concealed behavior under the soil and roots. The second stage juveniles (J-II) feed and reside in the roots that creates galls/knots on the roots which ultimately lead toward the death of the plant. Integrated approaches are advised to the growers to tackle these parasitic worms. The use of resistant varieties, crop rotation, chemical control and utilization of microbiota is necessary to keep their damages below economic threshold level.

### **Conflict of interest**

The authors declare no conflict of interest.

*Perspective Chapter: Integrated Root-Knot Nematodes* (Meloidogyne) *Management Approaches DOI: http://dx.doi.org/10.5772/intechopen.102882*
