Evaluation of seed dressing insecticides for the control of maize lethal necrosis vectors

Figures & data

Table 1. Descriptions of insecticides (treatments) used for seed treatment for control of maize lethal necrosis transmitting insect vectors and rates of application.

Trade name	Active ingredient	Treatment with code	Application rate (g/kg seed)
Apron Star 42% WS	thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%	T1 = Apron star 42% WS	2.5
		T2 = Apron star 42% WS	2.0
		T3 = Apron star 42 % WS	3.0
Imidalm T 450 WS	imidacloprid + thiram	T4 = Imidalm T 450 WS	1.0
		T5 = Imidalm T 450 WS	0.5
		T6 = Imidalm T 450 WS	1.5
Proseed Plus 63% WS	Imidacloprid + Thiram + Carboxin	T7 = Imidacloprid + Thiram + Carboxin	3.0
		T8 = Imidacloprid + Thiram + Carboxin	2.0
		T9 = Imidacloprid + Thiram + Carboxin	1.0
Evident 25% WG	Thiamethoxam	T10 = Thiamethoxam 25% WG	2.0
		T11 = Thiamethoxam 25% WG	1.0
		T12 = Thiamethoxam 25% WG	3.0
		T13 = Undressed seeds used as control	–

Table 2. Influence of seed treatment on the germination (%) of maize seeds stored for 1 and 6 months after insecticide treatment.

Treatment	Rate (product in g per 1 kg seed)	Germination (%)
		After 1-month storage	After 6-month storage
thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%	2.5	100.00a	100.00a
	2.0	100.00a	98.33ab
	3.0	98.33aa	98.33ab
Imidacloprid + thiram	1.0	100.00a	98.33ab
	0.5	98.33a	98.33ab
	1.5	98.33a	98.33ab
Thiamethoxam 25% WG	2.0	98.33a	95.00b
	1.0	96.67a	96.67ab
	3.0	96.67a	95.00b
Imidacloprid + Thiram + Carboxin	2.0	100.00a	98.33ab
	1.0	98.33a	98.33ab
	3.0	98.33a	98.33ab
Undressed seed	0	100.00a	98.33ab

Means followed by the same letters are not significantly different (p < 0.05).

Table 3. Effects of insecticidal maize seed treatment on thrips (Frankliniella sp.) population reduction in maize seedlings raised from treated seeds stored for 1 and 6 months.

Treatment	Seedlings derived from treated seeds stored for 1 month	Seedlings derived from treated seeds stored for 6 months
Thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%@2.5 g/kg	95.78e	81.78c
Thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%@2 g/kg	97.33bcd	84.11bc
Thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2% @3 g/kg	96.22cde	82.44c
Imidacloprid + thiram @1 g/kg	98.89a	85bc
Imidacloprid + thiram @0.5 g/kg	99.22a	82.44c
Imidacloprid + thiram @1.5 g/kg	99.11a	90.89ab
Imidacloprid + Thiram + Carboxin@3g/kg	97.22bcd	81.78c
Imidacloprid + Thiram + Carboxin@2g/kg	96.00de	73.56d
Imidacloprid + Thiram + Carboxin@1g/kg	91.11f	69.89d
Thiamethoxam 25% WG@2g/kg	98.33ab	93.78a
Thiamethoxam 25% WG@1g/kg	96.00de	91ab
Thiamethoxam 25% WG@3g/kg	97.44bc	98abc
Undressed seed	3.33g	2.44e

Means with the same letter are not significantly different (p ≤ 0.05).

Table 4. Effect of insecticidal maize seed treatment on maize leaf aphid (Rhopalosiphum maidis) population in maize seedlings derived from seeds stored for 1 and 6 months after treatment.

Treatment	Seedlings derived from treated seeds stored for 1 month	Seedlings derived from treated seeds stored for 6 months
Thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%@2.5 g/kg	97.19dc	87.85abc
Thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%@2 g/kg	98.22abc	90.15a
Thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2% @3 g/kg	97.48dc	88.3abc
Imidacloprid + thiram @1 g/kg	99.26ab	90.00a
Imidacloprid + thiram @0.5 g/kg	99.48a	88.30abc
Imidacloprid + thiram @1.5 g/kg	99.41a	93.93a
Imidacloprid + Thiram + Carboxin@3g/kg	97.78bc	88.89ab
Imidacloprid + Thiram + Carboxin@2g/kg	98abc	80.59c
Imidacloprid + Thiram + Carboxin@1g/kg	96.15d	81.03bc
Thiamethoxam 25% WG@2g/kg	98.15abc	95.85a
Thiamethoxam 25% WG@1g/kg	97.85bc	91.78a
Thiamethoxam 25% WG@3g/kg	98.52abc	93.41a
Undressed seed	2.08e	1.63d

Means with the same letter are not significantly different (p ≤ 0.05).

Table 5. Cumulative effects of different insecticidal seed dressers on MCMV and SCMV vectors, thrip (Frankliniella sp.). and (Rhopalosiphum maidis), respectively.

Treatment	Rate (g/kg maize seed)	Mean population reduction of thrips (Frankliniella sp.)	Mean population reduction of aphid (R. maidis)
Thiamethoxam 25% WG	2.0	96.06a	97.37a
Imidacloprid + thiram	1.5	95.00ab	96.67ab
Thiamethoxam 25% WG	1.0	93.50bc	94.56abc
Thiamethoxam 25% WG	3.0	93.22bc	95.85abc
Imidacloprid + thiram	1.0	91.95dc	94.63abc
Imidacloprid + Thiram + Carboxin	3.0	91.50de	93.33bc
Imidacloprid + thiram	0.5	90.83def	93.89bc
thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%	2.0	90.72def	94.18abc
thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%	3.0	89.89ef	92.89bcd
thiamethoxam 20% + metalaxyl – 20% + difenoconazole 2%	2.5	89.72f	92.52 cd
Imidacloprid + Thiram + Carboxin	2.0	84.78g	89.30de
Imidacloprid + Thiram + Carboxin	1.0	77.72h	87.77e
Undressed seed		2.89i	1.85f

Means are from both two treated seeds stored for 1 and 6 months. Means followed by the same letters are not significantly different (p < 0.05).

Data availability statement

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.