The fall armyworm, Spodoptera frugiperda (J.E. Smith), an invasive pest has recently spread to all over India and several other countries. For management of this pest, it is important to monitor moth activity by using pheromone traps. In the present study pheromone traps (Polythene sleeve type) baited with ‘GAIAGEN Lures’ (rubber septa) were installed @ 12 traps/ha in the experimental fields. The adult male moths caught during an observational week were counted. Per cent plant infestation was recorded at every seven days interval. The results have revealed that there was a gap of several weeks between peak field infestation and peak moth catch/trap, it indicates that field infestation was high even though moth trap catch was low and there is a negative association between the trap catches and per cent plant infestation. The relationship between field infestation (No. of larvae/plant and % plant infestation) and trap catches were negatively correlated for all the five weeks i.e., nth, (n-1)th, (n-2)th, (n-3)th, (n-4)th in both 2022-23 and 2023-24 years. There was no concrete evidence of field infestation taking place after adult trap catches. Therefore, it can be concluded that only pheromone trap catch data cannot be taken into consideration for timing insecticide application. Field scouting could be better option for monitoring fall armyworm in maize.

In 2-year field studies on seasonal incidence of rice leaf folder on rice variety MTU 7029, results revealed that the leaf folder infestation (0.56%) started in the rice field during the 2nd week of August (32nd standard week) and remained low to moderate throughout the tillering stage. The infestation was found to increase in the month of October and it reached the maximum level (6.01%) during the end of October (43rd standard week). It has also became evident from the study that minimum temperature have significant negative correlation (r = -0.493) with rice leaf folder percent infestation. Both the maximum and minimum relative humidity were negatively correlated but were not significant. Rainfall was also found to have significant negative correlation (r = -0.488) with the percent larval infestation. Correlation study between rice leaf folder percent infestation and plant phonological parameters like average tiller/hill, average leaf/tiller as well as Growing Degree Days (GDD) revealed that the percent infestation was strongly and positively correlated with GDD.

The experiment was conducted in Sericulture Research Laboratory and Instructional Farm of Bidhan Chandra Krishi Viswavidyalaya, North Bengal Campus, Pundibari, Cooch Behar with a view to standardize optimum quantity of mulberry leaves (variety S1) to be provided in rearing bed for bivoltine silkworm (P5×SH6) through manipulation of feeding number and rationing level to make the sericulture enterprise more remunerative for terai region of west Bengal. It was found that cocoon yield and its economic traits namely, larval weight, cocoon weight, shell weight, silk ratio percentage, effective rate of rationing in number and in weight etc. as well as quality parameters viz., filament length, filament weight, reelability, denier etc. were deteriorated with the increase level of rationing. Yield of cocoon (59.50 kg/100 dfls) and its economic traits, both quantitative and qualitative were found better by four daily feedings without any rationing of leaves, but five daily feedings (55.82 kg/100 dfls) with 20% rationing may also considered on overall performance of yield and quality of cocoon.

The incidence of yellow mite (Polyphagotarsonemus latus Banks) on different varieties of jute, sown at different dates during crop growing season revealed that the mite population was higher on early sown crop but decreased gradually with delay in sowings. Mite population was 49.75, 38.06 and 21.25 mites/5 leaves on crops sown on 2nd and 4th week of April and 2nd week of May, respectively. Among the two species of jute studied, population was always higher on the varieties of Olitorius as compared to Capsularis. Among the six varieties evaluated (JRC 212, JRC 7447 and JRC 321 of Capsularis and JRO 7835, JRO 632 and JRO 524 of Olitorius), JRO 7835 was found most susceptible (64.97 mites/5 leaves) and JRC 321 was least susceptible (16.39 mites/5 leaves). Peak population of mite was observed during 3rd week of June irrespective of varieties and date of sowing. No relation has been found between building up of population and age of the crop; rather it was dependent upon the prevailing weather conditions.

The seasonal incidence of thrips and the preference for the placement of leaf were assessed for the distribution of population on different positions of leaves. Thrips were prevalent throughout the year. The maximum was observed during April, followed by June–July and the lowest being during winter months, i.e., December–January. The increase in its population was positively correlated with higher temperature, relative humidity and rainfall but negatively correlated with difference between maximum and minimum temperature. Maximum thrips population was confined on third, fourth and fifth leaf (49.39%) from the top.

Multiple correlation studies were carried out to assess the influence of important weather factors on the population fluctuation of insect pests of mandarin orange (Citrus reticulata Blanco) at Pedong, West Bengal during 1996 and 1997. The incidence of citrus brown aphid (Toxoptera citricidus (Kirk.) had a significant positive association with rainfall. Similarly, back fly (Aleurocanthus woglumi (Ashby)) population significantly increased with the increase in R.H. and rainfall. Abundance of helmet scale (Saissetia coffeae (Walker)) showed positive association with maximum temperature, R.H. and rainfall, but an inverse relation was observed with minimum temperature. In the case of soft brown scale (Coccus hesperidium Linnaeus), an identical relationship existed only with maximum and minimum temperatures. The infestation of citrus dog (Papilio demoleus Linnacus) increased significantly with the increase in maximum temperature and R.H., but leaf folder (Psorosticha zizyphi Staint.) showed a significant negative association with rainfall and positive correlation with R.H. However, individual weather parameter had no such influence on the other frequently observed insect species of mandarin orange.

Three varieties of mulberry namely 51, TRIO and Kosen were taken for this purpose during 1994–95. Among them Kosen showed better response regarding larval and cocoon traits than TR10 and S1 though the difference among these three varieties was not significant for all the traits studied so far. All the traits viz., larval weight, cocoon weight, shell weight, silk ratio, ERR in number and weight showed positive correlation with cocoon yieId and negative correlation with room temperature and relative humidity.

An experiment was conducted for 2 year; durig 1994-96 at Cooch Behar to evaluate the relative performance of 7 bivoltine silkworm breeds namely P-5, KPG(B), SH6 NE18, P-5 x KPG(B), KPG(B) x P-5 and P-5 x SE6 against occurrence of different diseases during different seasons, viz February-March, March-April, May-June, June-July, August-September, October-November and November-December. It is observed that SH6 and its hybrids with P-5 showed higher survivality against different diseases over seasons, indicates their suitability for terai region of West Bengal. Incidence of different diseases was found maximum during May to September and minimum during February to April and again in October to December.