Determination of most effective insecticides against maize fall armyworm, Spodoptera frugiperda in South Western Ethiopia

Figures & data

Table 1. Insecticide and rate of application used for the management of maize fall armyworm during the experimental period

Treatment Insecticide	Trade Name	Class	Dos of a. I (L/ha)
Malathion 50EC	Ethiolathion 50% EC	Organophosphate	1 L
Diazinon 48% EC	Ethiozinon 60% EC	Organophosphate	1.2 L
Alpha cypermethrin	Fasted 10% EC	Pyrethroid	0.4 L
Deltamethrin	Ethiodemethrin 2.5% EC	Pyrethroid	15,000 mL
Lambda-cyhalothrin	Karate 2.5% EC	Pyrethroid	200 mL
Dimethoate 40%	Agro-Thoate 40%EC	Organophosphate	900 mL

Table 2. Percent mean mortality of maize FAWs treated with different insecticide at laboratory condition (n = 10)

Treatment	Dos of a. i	% larval Mortality S. frugiperda (± SE)
	(L/1 m^2)	24hrs	48hrs	72hrs
Deltamethrin	0.002	96.67 ± 9.7^a	100.00 ± 10a	100.00 ± 10a
Malathion	0.0012	83.33 ± 8.3^ab	96.67 ± 9.7a	100.00 ± 10a
Alpha-Cypermethrin	0.0004	76.67 ± 7.7^b	100.00 ± 10a	100.00 ± 10a
Dimethoate	0.015	86.67 ± 8.7^ab	93.33 ± 9.3a	100.00 ± 10a
Diazinon	0.0002	86.67 ± 8.7^ab	100.00 ± 10a	100.00 ± 10a
Lambda-cyhalothrin	0.0009	83.33 ± 8.3^ab	96.67 ± 9.7a	100.00 ± 10a
Control	-	6.67 ± 0.7^c	6.67 ± 0.7b	3.33 ± 0.3b
LSD		1.52	0.76	0.38
CV		11.7	5.1	2.53

Table 3. Mean larval population of S. frugiperda on different maize cultivars grown under plot experiment using irrigation system

Treatment	Mean no. of larval population/Plot (±SME)
	Day 1 ^BIA	Day 2 ^BIA	Day 3 ^BIA
Argane	1.33 ^cd	4.00^b	9.67^b
BH-540	5.00^b	9.33^a	9.33^b
Jibat	0.67^d	2.33^bc	5.67^bc
Kulani	1.00 ^cd	2.00^bc	5.00^c
Limmu	2.33^c	1.67^c	4.33^c
Shone	6.67^a	11.33^a	14.33^a
Wenchi	5.00^b	4.00^b	5.00^c
LSD (0.05) *	1.49	3.63	4.11
CV	26.59	25.69	30.33

Mean in which the same letters are not significantly different from one another. BIA = Before Insecticide application

Table 4. Mean percent of damaged maize cultivars (leaf, and whorls) against S. frugiperda under plot experiment, pre-insecticide applications

Treatment	Mean no. of damaged maize plant/Plot			Mean % of damaged maize plant /Plot
	Day 1 ^BIA	Day 2 ^BIA	Day3 ^BIA
Argane	4.33^ab	8.00^bc	9.33^b	7.22
BH-540 (control)	3.33^b	9.33^ab	15.33^ab	9.33
Jibat	3.00^b	9.00^ab	14.00^ab	8.67
Kulani	3.00^b	9.67^ab	10.33^b	7.67
Limmu	4.33^ab	10.67^ab	14.67^ab	9.89
Shone	6.00^a	11.67^a	18.67^a	12.11
Wenchi	3.67^b	5.67^c	10.33^b	6.56
LSD (0.05) *	2.01	3.49	6.28
CV	24.69	19.95	26.67

Mean in which the same letters are not significantly different from one another. BIA = Before Insecticide application.

Table 5. Mean infestation reduction/Plot of maize plant against larvae of S. frugiperda after spraying of insecticide under irrigated plot experiment

Treatment	Rate a.i (mL/m^2)	Mean% Infestation reduction/Plot		Average infested maize plant /Plot
		Day3 AIA	Day 4 AIA
Argane* Dimethoate	2.43 ml	1.67^d	1.33^c	1.5
Jibat*Malathion	2.7 ml	2.00 ^cd	1.00^c	1.5
Kulani*Diazinon	3.24 ml	1.67^d	2.33^c	2
Limmu * Deltamethrin	40.5 ml	4.00^b	6.67^b	5.2
Shone* Alpha Cypermethrin	1.08 ml	3.33^bc	9.00^b	6.2
Wenchi*Lambda-cyhalothrin	0.81 ml	1.33^d	1.67^c	1.5
BH-540* Check	-	11.67^a	14.00^a	12.81
LSD (0.05) *		1.7	2.65
CV		24.66	28.99

Numbers within columns followed by the same letter are not statistically different (LSD; P = 0.05). AIA = After Insecticide Application

Figure 1. Correlation between the infestation of maize cultivars and efficacy of insecticide against S. frugiperda. a. FAW infestation and effect of Alpha-Cypermethrin with time. b. FAW infestation and effect of Dimethoate with time. c. FAW infestation and effect of Diazinon with time. d. FAW infestation and effect of Lambda-cyhalothrin with time. e. FAW infestation and effect of Deltamethrin with time. f. FAW infestation and effect of Deltamethrin with time.

Table 6. Mean % mortality of larvae per plot after treated with insecticide application, efficacy test

Treatment	Mean % Mortality of larvae /plot (MSE)
	1-day ^AIA	3-days ^AIA
Deltamethrin	23.33 ± 2.33^b	30.3 ± 3.00^a
Alpha Cypermethrin	40 ± 4.00^a	30.3 ± 3.00^a
Dimethoate	23.33 ± 2.33^b	26.67 ± 2.67^a
Lambda-cyhalothrin	23.33 ± 2.33^b	26.67 ± 2.67^a
Diazinon	16.67 ± 1.67^bc	16.67 ± 1.67^ab
Malathion	10.00 ± 1.00^c	20 ± 2.00^ab
Control (untreated treatment)	10.00 ± 1.00^c	1 ± 0.67^b
LSD (0.05) *	0.95	1.50
CV	25.51	37.76

Mean with a same letter were sharing significantly different at (P < 0.05) using Tukey's test. AIA = after insecticide application.

Table 7. Mean number of S. frugiperda captured (pest density) and infestation level before the application of selected insecticide in the farmers maize field

Location (treatment)	Mean number of FAW adult captured (± SEM)
	July. 30. 2020 *D1^st 28d	August. 4. 2020 *D1^st 32d	August. 8. 2020 *D1^st 36d
Tulu Sangota (b)	33.00^a	38.33^a	36.00^a
Gara Gona	24.67^b	26.00^b	30.67^ab
Jalale	25.00^b	24.33^b	25.33^bc
Tulu Sangota (a)	23.67^b	29.00^ab	24.33^c
Bilo Boshe	21.33^b	21.00^b	20.00^c
LSD (0.05) *	4.99	12.10	6.50
CV	10.39	23.19	12.67

Mean with a same letter were sharing significantly different at (P < 0.05) using Tukey's test. *D1^st 30d = during the 1^st 28 days,

Figure 2. Infestation and severity of maize fall army worm, S. frugiperda in the various locations of south western Ethiopia.

Table 8. Mean % reduction of maize leaf and whorl damage by S. frugiperda in the farmers maize plot exposed to insecticides

TRT	Dose (L/ha)	Mean % reduction of maize leaf and whorl damage (mean ± SE)
		Day 1 ATA*	Day 2 ATA*	Day 3ATA*
Bilo Boshe—Lambda-cyhalothrin	320 ml	18 ± 7.33^b	15.67 ± 7.00^b	7 ± 4.67^b
Tulu Sangota (a)- Dimethoate	1.5 L	8 ± 5.00^b	4.67 ± 4.00^c	3 ± 2.67^b
Tulu Sangota (b)-Deltamethrin	20–25 ml	5 ± 3.67^b	6.33 ± 4.67^bc	6.33 ± 4.33^b
Gara Gona -Alpha-Cypermethrin	25 ml	8 ± 5.00^b	6 ± 4.00^c	9.33 ± 5.67^b
Jalale—Control (no chemical trt)	-	231 ± 27.00^a	217.33 ± 26.33^a	258 ± 28.33^a
Mean		54	50	56.7
LSD (0.05) *		3.88	2.89	4.33
CV		21.52	16.72	25.21

Means within columns followed by a common letter are not significantly different (P ≤ 0.05Tukey’s Studentized Range Test). ATA* (after treatment application)