Fall armyworm, Spodoptera frugiperda (J.E. Smith) Damage on Rice in the Philippines

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FAW-infested areas in the Philippines
The locations where FAW infestations were observed are presented in Table 1 and Figure 1.A week after the first reported FAW infestation in Cagayan in 2021, a follow-up visit cum validation was conducted in the neighboring barangay of Callao in Gonzaga, Cagayan (18° 16' 08.0" N, 121° 59' 30.5"E), wherein 276 larvae/m 2 with an assessed crop damage of 60% were observed in the inbred NSIC Rc222 seedlings, and 32 larvae/m 2 in the hybrid Longping 2096 rice seedlings aged about 20-25 days after seeding (DAS) were recorded (Table 1).It was further observed that different growth stages of FAW were present during the validation activities (Figure 2.) High population of FAW larvae were also documented in Rapuli, Santa Ana, Cagayan (Figure 3).With the continued monitoring activities during the months of May and June 2021, more FAW attacks were recorded in the rice seedbeds and in some of the direct-seeded rice at seedling stage in 14 municipalities in Region 2 (Valdez et al., 2021;Valdez et al., 2023).In May 2022, Valdez et al. (2023) reported that a re-invasion was observed in nine barangays in Gonzaga and one barangay in Santa Ana, Cagayan wherein FAW in the seedbeds were again documented (Figure 4 A & B).Further, the first reported FAW occurrence and damage in the province of Nueva Ecija were recorded in June 2022.
Anticipating a recurring FAW invasion in 2023, monitoring activities were intensified particularly in Cagayan (Gonzaga and Santa Ana).Consequently, FAW was again documented in some barangays of Gonzaga and Santa Ana on May 17-18, 2023.On May 17, 2023, 8 larvae/m 2 was recorded with 16.67% damage in Flourishing, Gonzaga, Cagayan (18 o 15' 12.9" N, 121 o 59' 58.9" E) wherein it was very near the area (18 o 15'7.7476"N, 121 o 59'54.9823"E) where the reported FAW re-invasion was documented the previous year of the same month.On the following day (May 18), FAW infestations were again recorded in some seedbeds in Rapuli, Santa Ana, Cagayan wherein one seedbed of NSIC Rc 402 was infested with an average of 87 larvae/m 2 with approximately 40% damage (Table 1, Figure 5).Further, in barangay Smart, Gonzaga, Cagayan several seedbeds of different rice varieties (hybrids LongPing 534, Pioneer 79, NK 5017 and the inbred NSIC Rc222) were attacked by FAW though the population was already low (1-8 larvae/1m 2 ) with some dead larvae observed due to the frequent application of insecticides.Some of the interviewed farmers of the FAW-infested seedbeds in both municipalities said that the insecticides they applied were Chlorpyrifos, Methomyl, Cypermethrin, Chlorantraniliprole, Lambdacyhalothrin, and Lufenuron.These insecticides were applied singly or as a mixture of two and applied 1 to 4 times before pulling of seedlings at 3-8 days interval starting at the time when the farmers observed the damage on the foliage.The FAW sightings for this year were observed in seedbeds areas undergoing pulling of seedlings activities wherein the seedlings were mostly aged 21 days after sowing (DAS) or younger.Majority of the FAW larvae observed were 4 th to 6 th instars with some pupae and adults.Recently this July 2023, FAW sightings were documented in one farmer's field outside of Philippine Rice Research Institute Central Experiment Station (15˚ 40' 43.8751" N, 120˚ 53' 30.3212"E) but only one larva was collected with several pupae of FAW and other defoliators.The seedbed of NSIC Rc222 was completely destroyed hence it was plowed under.Also, some rice seedbeds of the experimental field of PhilRice Central Experiment Station (15˚ 40' 22.9771" N, 120˚ 53' 35.1686"E) were severely infested (Figure 6A & B) by FAW larvae with an average of 16-19 larvae/m 2 and a damage of 60-90% in NSIC Rc622, NSIC Rc624 and NSIC Rc626.Seedlings of NSIC Rc632 and NSIC Rc636 grown in the same area as the three varieties previously mentioned were also attacked by FAW larvae but not as severe as the larvae were mostly at 6 th instar and pre-pupation stage.Some FAW larvae were also collected in barangay Camanacsacan, San Jose City, Nueva Ecija (15˚ 46' 20.2235" N, 15˚ 46' 20.2235" N).In all the locations, the damage caused by FAW to rice seedlings was observed as a combination of cut leaves and cut plants up to ground level (Figure 6A & B).

Future Directions
Since the first report of FAW on rice in the Philippines in 2021, it was observed that it consistently attacks the rice seedlings during the months of May, June and July.It is also spreading from Region 2 to Region 3. FAW occurrence during seedling stage in the seedbed will be easier to manage since the area is smaller, but the misuse and abuse of pesticides can trigger crop losses from other minor pests.In addition, if the seedlings are completely damaged due to FAW attack, the crop establishment will be delayed thereby prone to attack by pests such as stemborer, brown planthopper and other pests and diseases.This can be catastrophic in the hybrid rice seed production where damage to one of the parents will result in poor seed setting and hybrid vigor.Direct-seeded rice at seedling stage is also vulnerable to FAW attack although direct-seeding technology has been promoted as labor-saving.There is a need to continuously monitor FAW presence and spread in the country and to develop a standard damage assessment protocol to determine the FAW density.
Early interventions to prevent significant yield losses are crucial in addition to the formulation of an effective location-specific management strategy with naturebased solutions.A B

Figure 2 .1
Figure 2. Rice seedlings with larva and pupa of FAW as well as the damage in leaves observed in Callao, Gonzaga, Cagayan in 2021.(Photo credits: Dindo King Donayre).

Figure 6 .
Figure 6.(A) FAW damage in rice seedlings pruned to the ground level.(B) Cut leaves serving as pathway or floaters to FAW larvae to transfer to other plants or weeds that were along the bunds, PhilRice Central Experiment Station, July 18, 2023.(Photo credits: Kennedy dela Cruz).