Incidence and population dynamics of various insect-pests at the vegetative stage of 11 selected genotypes was shown in Table 1. The maximum incidence and population dynamics of
Scirpophaga incertulus was recorded in Varsha Dhan and Luna Sankhi cultivars with 3.67 larvae/ tiller followed by Arize 8433 and Bhuban with 3.34 and Chandra with 3.00 larvae/ tiller of rice, respectively. The minimum incidence and population dynamics of
Scirpophaga incertulus was recorded in BAM-6 with 2.00 and CR Dhan 306 with 2.34 larvae/tiller of rice, respectively. The maximum incidence and population dynamics of
Orseolia oryzae was recorded in Chandra with 2.67 larvae/tiller followed by Sumit with 2.34 and CR Dhan 100, CR Dhan 306 and Luna Sankhi with 2.00 larvae/tiller of rice, respectively. The minimum incidence and population dynamics of
Orseolia oryzae was recorded in BAM-6 with 0.67 larvae/tiller followed by Varsha Dhan, Bhuban and Anjali with 1.34 larvae/tiller of rice, respectively. The maximum incidence and population dynamics of
Nilaparvata lugens was found to be non-significant for all of the selected cultivars, however, in case of
Sogatella frucifera, low incidence was recorded in Varsha Dhan with 1.34 nymphs which stands maximum followed by Bhuban and Sumit with 0.67 and 0.34 nymphs/tiller, respectively.
The maximum incidence and population dynamics of
Cnaphalocrocis medinalis was recorded in Bhuban cultivar with 5.34 larvae/tiller of rice followed by Chandra with 5.00 and Anjali with 4.34 larvae/tiller of rice. The minimum incidence was noted in case of Vandana with 2.67 larvae/tiller of rice followed by Sumit 3.34 and CR Dhan 306 with 3.67 larvae/tiller of rice. The maximum incidence and population dynamics of
Parapoynx stagnalis was recorded in Arize 8433 with 2.67 larvae/tiller of rice followed by Luna Sankhi with 2.34 and BAM-6 and Sumit 2.00 larvae/tiller of rice. The incidence and population dynamics of
Scirpophaga incertulus, Orseolia oryzae, Cnaphalocrocis medinalis, Parapoynx stagnalis was found to be significant in almost all of the selected cultivars but a few of them showed greater favourable response against these pests which was likely due to late sowing of the rice in this region. This result was also slightly similar to previous work
(Graf et al., 1992; Karuppaiah and Sujayanad, 2012;
Kraker et al., 1999). The incidence of various sucking pests was non-significant in case of
Nilaparvata lugens, however, in case of
Sogatella frucifera, low incidence has been recorded inVarsha Dhan with a very negligible population count which was in agreement with previous reports of
Cohen et al., (1994); Raju et al. (2021) and
Verma et al., (2021). The direct sown rice appears to be bit more convenient for pests to seek shelter and feed on compared to the transplanted rice which took more time to establish in the fields
(Lamba and Dono, 2021;
Zhao et al., 2021).
The data presented in the Table 2 show the maximum incidence of
Dicladispa armigera (Grub and adults) was recorded in BAM-6 and CR Dhan 306 with 2.67 followed by Bhuban and Sumit with 2.00 and Arize 8433 with 1.34 larvae/tiller of rice, respectively. The maximum incidence and population dynamics of
Leptocorisa acuta (nymph and adults) was recorded in CR Dhan 100 with 5.34 followed by Arize 8433, CR Dhan 306 with 5.00 and Chandra, Vandana with 4.67 nymph and adults
Leptocorisa acutaper tiller of rice, respectively. The maximum incidence and population dynamics of various Grasshoppers (Nymph and adults) were recorded in CR Dhan 100 with 7.34 followed by Chandra, Vandana with 6.67 and Anjali with 6.34 grasshoppers per tiller while the minimum population of grasshoppers were recorded in CR Dhan 306 with 4.00 followed Sumit, Varsha Dhan, BAM-6 with 5.34 grasshoppers per tiller of rice.
The distribution of pests like
Dicladispa armigera and
Melantis leda was sporadic in nature and the incidence was reported to be very low from various assessed fields, which majorly depends on topography and climatic conditions of the given area
(Nagdev et al., 2022; Das et al., 2021; Verma et al., 2021; Morya and Kumar, 2021;
Askary and Ahmad, 2021;
Xu et al., 2022 and
Nam et al., 2020).
The incidence and population dynamics of various insect-pests at the milking stage of rice during
Kharif 2021 was shown in Table 3. The maximum incidence and population dynamics of
Scirpophaga incertulus at the milking stage in various farmers shown cultivars were found in Chandra with 2.67 larvae/tiller followed by Luna Sankhi, Varsha Dhan and Bhuban with 2.34 larvae/tiller. The minimum values of
Scirpophaga incertulus infestation at milking stage in various farmers shown cultivars were recorded in Anjali, BAM-6, CR Dhan 100 and Vandana with 1.34 larvae/tiller.
The incidence and population dynamics of
Orseolia oryzae in various farmer shown rice cultivars shown in Table 3 in which, the maximum incidence and population dynamics of
Orseolia oryzae were recorded in Luna Sankhi, CR Dhan 100 and Anjali with 2.67 larvae/tiller followed by Vandana with 2.34 larvae/tiller, while minimum values were seen in BAM-6 with 1.34 larvae/tiller followed by Bhuban, Varsha Dhan with 1.67 larvae/tiller. The incidence and population dynamics of
Cnaphalocrocis medinalis in various farmer shown rice cultivars is presented in Table 3, in which maximum incidence and population dynamics of
Cnaphalocrocis medinalis was recorded in Bhuban with 6.34 larvae/tiller followed by the Anjali with 5.67 and Luna Sankhi, Varsha Dhan with 5.34 larvae/tiller while minimum values were recorded in Vandana with 3.67 larvae/tiller followed by Sumit with 4.00 and Arize 8433 with 4.34 larvae/tiller. The milking stage of rice growth attract much more pests in compared to the vegetative stage due to high amount of fragrance and other stimuli produced by various portions of crop plants
(Bisen et al., 2019;
Mohanta et al., 2020; Chou et al., 2022; Han et al., 2018). The larval population of various pests like
Scirpophaga incertulus, Orseolia oryzae, Cnaphalocrocis medinalis, Parapoynx stagnalis increases with the increase of vegetations. The growth of hosts is directly proportional to the population of various phytophagy
(Mandloi et al., 2018; Nasrullah and Rafsanjani, 2022 and
Khanpara et al., 2020).
The incidence and population dynamics of various insect-pests at the milking stage of rice during
Kharif 2021 is shown in Table 4. The incidence and population dynamics of
Dicladispa armigera which were recorded maximum in the CR Dhan 306, BAM-6 with 3.34 grub and adults/tiller followed by Sumit, Bhuban with 2.67 grub and adults/tiller. The minimum values of incidence and population dynamics were seen in Anjali, CR Dhan 100, Luna Sankhi and Vandana with 1.67 grub and adults/tiller. The incidence and population dynamics of
Leptocorisa acuta, which were recorded maximum in CR Dhan 306, BAM-6Arize 8433 with 3.34 nymphs and adults/tiller followed by CR Dhan 100, Anjali with 6.67 nymphs and adults/tiller. The minimum incidence and population dynamics values were recorded in BAM-6, Chandra, Varsha Dhan, Vandana with 5.34 nymphs and adults/tiller.
The incidence and population dynamics of
Nephotettix virescens, shown in Table 4 and was recorded maximum in CR Dhan 306, Bhuban with 8.34 nymphs and adults/tiller followed by Vandana, Varsha Dhan, Anjali with 7.67 nymphs and adults/tiller. The incidence and population dynamics of
Melantis leda, which were recorded maximum in the Luna Sankhi,Varsha Dhan with 8.34 larvae and pupae/tiller followed by Bhuban with 1.34 larvae and pupae/tiller. The incidence and population dynamics of
Mythimna separata, was recorded maximum in Anjali with 5.67 larvae/tiller followed by Vandana, Sumit, Varsha Dhan, CR Dhan 100, BAM-6 with 5.34 larvae/tiller. The minimum incidence and population dynamics values were seen in Arize 8433 with 4.34 larvae/tiller followed by Bhuban, Chandra with 4.67 larvae/tiller. Pests like
Leptocorisa acuta and
Nezara virdula showed more incidences during the flowering and milking stages as they prefer to feed mainly on the milking grains
(Budiarti et al., 2022; Darmiati et al., 2018; Rahayu et al., 2018 and
Siregar, 2021). Grasshoppers and
Mythimna separate are considered to be foliage feeders of rice and can be found all over the rice fields during all the stages
(Sugiarto, 2018;
Mahesh et al., 2016; Cui et al., 2019 and
Hussain et al., 2017).
